Nanomaterials

13 pages, 2978 KiB

Open AccessEditor’s ChoiceArticle

Scanning Photocurrent Microscopy in Single Crystal Multidimensional Hybrid Lead Bromide Perovskites

by Elena Segura-Sanchis, Rocío García-Aboal, Roberto Fenollosa, Fernando Ramiro-Manzano and Pedro Atienzar

Nanomaterials 2023, 13(18), 2570; https://doi.org/10.3390/nano13182570 - 16 Sep 2023

Cited by 1 | Viewed by 960

Abstract

We investigated solution-grown single crystals of multidimensional 2D–3D hybrid lead bromide perovskites using spatially resolved photocurrent and photoluminescence. Scanning photocurrent microscopy (SPCM) measurements where the electrodes consisted of a dip probe contact and a back contact. The crystals revealed significant differences between 3D [...] Read more.

We investigated solution-grown single crystals of multidimensional 2D–3D hybrid lead bromide perovskites using spatially resolved photocurrent and photoluminescence. Scanning photocurrent microscopy (SPCM) measurements where the electrodes consisted of a dip probe contact and a back contact. The crystals revealed significant differences between 3D and multidimensional 2D–3D perovskites under biased detection, not only in terms of photocarrier decay length values but also in the spatial dynamics across the crystal. In general, the photocurrent maps indicate that the closer the border proximity, the shorter the effective decay length, thus suggesting a determinant role of the border recombination centers in monocrystalline samples. In this case, multidimensional 2D–3D perovskites exhibited a simple fitting model consisting of a single exponential, while 3D perovskites demonstrated two distinct charge carrier migration dynamics within the crystal: fast and slow. Although the first one matches that of the 2D–3D perovskite, the long decay of the 3D sample exhibits a value two orders of magnitude larger. This difference could be attributed to the presence of interlayer screening and a larger exciton binding energy of the multidimensional 2D–3D perovskites with respect to their 3D counterparts. Full article

(This article belongs to the Special Issue Innovative Nanomaterial Properties and Applications in Chemistry, Physics, Medicine, or Environment)

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26 pages, 23610 KiB

Open AccessEditor’s ChoiceArticle

Innovative Low-Cost Composite Nanoadsorbents Based on Eggshell Waste for Nickel Removal from Aqueous Media

by Adina-Elena Segneanu, Roxana Trusca, Claudiu Cepan, Maria Mihailescu, Cornelia Muntean, Dumitru Daniel Herea, Ioan Grozescu and Athanasios Salifoglou

Nanomaterials 2023, 13(18), 2572; https://doi.org/10.3390/nano13182572 - 16 Sep 2023

Cited by 1 | Viewed by 1105

Abstract

In a contemporary sustainable economy, innovation is a prerequisite to recycling waste into new efficient materials designed to minimize pollution and conserve non-renewable natural resources. Using an innovative approach to remediating metal-polluted water, in this study, eggshell waste was used to prepare two [...] Read more.

In a contemporary sustainable economy, innovation is a prerequisite to recycling waste into new efficient materials designed to minimize pollution and conserve non-renewable natural resources. Using an innovative approach to remediating metal-polluted water, in this study, eggshell waste was used to prepare two new low-cost nanoadsorbents for the retrieval of nickel from aqueous solutions. Scanning electron microscopy (SEM) results show that in the first eggshell–zeolite (EZ) adsorbent, the zeolite nanoparticles were loaded in the eggshell pores. The preparation for the second (iron(III) oxide-hydroxide)–eggshell–zeolite (FEZ) nanoadsorbent led to double functionalization of the eggshell base with the zeolite nanoparticles, upon simultaneous loading of the pores of the eggshell and zeolite surface with FeOOH particles. Structural modification of the eggshell led to a significant increase in the specific surface, as confirmed using BET analysis. These features enabled the composite EZ and FEZ to remove nickel from aqueous solutions with high performance and adsorption capacities of 321.1 mg/g and 287.9 mg/g, respectively. The results indicate that nickel adsorption on EZ and FEZ is a multimolecular layer, spontaneous, and endothermic process. Concomitantly, the desorption results reflect the high reusability of these two nanomaterials, collectively suggesting the use of waste in the design of new, low-cost, and highly efficient composite nanoadsorbents for environmental bioremediation. Full article

(This article belongs to the Special Issue Nanomaterials for Green and Sustainable World)

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21 pages, 3667 KiB

Open AccessEditor’s ChoiceArticle

The Apoptosis Inhibitor Protein Survivin Is a Critical Cytoprotective Resistor against Silica-Based Nanotoxicity

by Christina Breder-Bonk, Dominic Docter, Matthias Barz, Sebastian Strieth, Shirley K. Knauer, Désirée Gül and Roland H. Stauber

Nanomaterials 2023, 13(18), 2546; https://doi.org/10.3390/nano13182546 - 12 Sep 2023

Viewed by 1169

Abstract

Exposure to nanoparticles is inevitable as they become widely used in industry, cosmetics, and foods. However, knowledge of their (patho)physiological effects on biological entry routes of the human body and their underlying molecular mechanisms is still fragmented. Here, we examined the molecular effects [...] Read more.

Exposure to nanoparticles is inevitable as they become widely used in industry, cosmetics, and foods. However, knowledge of their (patho)physiological effects on biological entry routes of the human body and their underlying molecular mechanisms is still fragmented. Here, we examined the molecular effects of amorphous silica nanoparticles (aSiNPs) on cell lines mimicking the alveolar-capillary barrier of the lung. After state-of-the-art characterization of the used aSiNPs and the cell model, we performed cell viability-based assays and a protein analysis to determine the aSiNP-induced cell toxicity and underlying signaling mechanisms. We revealed that aSiNPs induce apoptosis in a dose-, time-, and size-dependent manner. aSiNP-induced toxicity involves the inhibition of pro-survival pathways, such as PI3K/AKT and ERK signaling, correlating with reduced expression of the anti-apoptotic protein Survivin on the protein and transcriptional levels. Furthermore, induced Survivin overexpression mediated resistance against aSiNP-toxicity. Thus, we present the first experimental evidence suggesting Survivin as a critical cytoprotective resistor against silica-based nanotoxicity, which may also play a role in responses to other NPs. Although Survivin’s relevance as a biomarker for nanotoxicity needs to be demonstrated in vivo, our data give general impetus to investigate the pharmacological modulation of Survivin`s functions to attenuate the harmful effects of acute or chronic inhalative NP exposure. Full article

(This article belongs to the Section Biology and Medicines)

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15 pages, 6006 KiB

Open AccessEditor’s ChoiceArticle

Encapsulation of Iron-Saturated Lactoferrin for Proteolysis Protection with Preserving Iron Coordination and Sustained Release

by Przemysław Gajda-Morszewski, Anna Poznańska, Cristina Yus, Manuel Arruebo and Małgorzata Brindell

Nanomaterials 2023, 13(18), 2524; https://doi.org/10.3390/nano13182524 - 8 Sep 2023

Viewed by 898

Abstract

Lactoferrin (Lf) is a globular glycoprotein found mainly in milk. It has a very high affinity for iron(III) ions, and its fully saturated form is called holoLf. The antimicrobial, antiviral, anticancer, and immunomodulatory properties of Lf have been studied extensively for the past [...] Read more.

Lactoferrin (Lf) is a globular glycoprotein found mainly in milk. It has a very high affinity for iron(III) ions, and its fully saturated form is called holoLf. The antimicrobial, antiviral, anticancer, and immunomodulatory properties of Lf have been studied extensively for the past two decades. However, to demonstrate therapeutic benefits, Lf has to be efficiently delivered to the intestinal tract in its structurally intact form. This work aimed to optimize the encapsulation of holoLf in a system based on the versatile Eudragit^® RS polymer to protect Lf against the proteolytic environment of the stomach. Microparticles (MPs) with entrapped holoLf were obtained with satisfactory entrapment efficiency (90–95%), high loading capacity (9.7%), and suitable morphology (spherical without cracks or pores). Detailed studies of the Lf release from the MPs under conditions that included simulated gastric or intestinal fluids, prepared according to the 10th edition of the European Pharmacopeia, showed that MPs partially protected holoLf against enzymatic digestion and ionic iron release. The preincubation of MPs loaded with holoLf under conditions simulating the stomach environment resulted in the release of 40% of Lf from the MPs. The protein released was saturated with iron ions at 33%, was structurally intact, and its iron scavenging properties were preserved. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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18 pages, 5701 KiB

Open AccessEditor’s ChoiceArticle

Selective Growth of MAPbBr₃ Rounded Microcrystals on Micro-Patterned Single-Layer Graphene Oxide/Graphene Platforms with Enhanced Photo-Stability

by Javier Bartolomé, María Vila, Carlos Redondo-Obispo, Alicia de Andrés and Carmen Coya

Nanomaterials 2023, 13(18), 2513; https://doi.org/10.3390/nano13182513 - 8 Sep 2023

Viewed by 1152

Abstract

The synergistic combination of hybrid perovskites with graphene-related materials is leading to optoelectronic devices with enhanced performance and stability. Still, taking advantage of the solution processing of perovskite onto graphene is especially challenging. Here, MAPbBr₃ perovskite is grown on single-layer graphene/graphene oxide [...] Read more.

The synergistic combination of hybrid perovskites with graphene-related materials is leading to optoelectronic devices with enhanced performance and stability. Still, taking advantage of the solution processing of perovskite onto graphene is especially challenging. Here, MAPbBr₃ perovskite is grown on single-layer graphene/graphene oxide (Gr/GO) patterns with 120 µm periodicity using a solution-processed method. MAPbBr₃ rounded crystals are formed with sizes ranging from nanometers to microns, either forming continuous films or dispersed particles. A detailed morphological and structural study reveals a fully oriented perovskite and very different growth habits on the Gr/GO micro-patterns, which we relate to the substrate characteristics and the nucleation rate. A simple method for controlling the nucleation rate is proposed based on the concentration of the precursor solution and the number of deposited perovskite layers. The photoluminescence is analyzed in terms of the crystal size, strain, and structural changes observed. Notably, the growth on top of Gr/GO leads to a huge photostability of the MAPbBr₃ compared with that on glass. Especially outstanding is that of the microcrystals, which endure light densities as high as 130 kW/cm². These results allow for anticipating the design of integrated nanostructures and nanoengineered devices by growing high-stability perovskite directly on Gr/GO substrates. Full article

(This article belongs to the Special Issue Perovskite Nanomaterials for Solar Cells and Optoelectronic Applications)

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12 pages, 4149 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Cellulose Nanofibres on Dewatering during Wet-Forming and the Mechanical Properties of Thermoformed Specimens Made of Thermomechanical and Kraft Pulps

by Eirik Ulsaker Jacobsen, Simen Prang Følkner, Jørgen Blindheim, Dag Molteberg, Martin Steinert and Gary Chinga-Carrasco

Nanomaterials 2023, 13(18), 2511; https://doi.org/10.3390/nano13182511 - 7 Sep 2023

Cited by 2 | Viewed by 1307

Abstract

Due to environmental concerns regarding single-use plastic materials, major efforts are being made to develop new material concepts based on biodegradable and renewable resources, e.g., wood pulp. In this study, we assessed two types of wood pulp fibres, i.e., thermomechanical pulp (TMP) and [...] Read more.

Due to environmental concerns regarding single-use plastic materials, major efforts are being made to develop new material concepts based on biodegradable and renewable resources, e.g., wood pulp. In this study, we assessed two types of wood pulp fibres, i.e., thermomechanical pulp (TMP) and Kraft pulp fibres, and tested the performance of the fibres in wet-moulding and thermopressing trials. Kraft pulp fibres appeared to retain more water than TMP, increasing the dewatering time during wet-moulding and apparently increasing the compression resistance of the pulp during thermoforming. Additionally, cellulose nanofibres (CNF) were added to the pulps, which improved the mechanical properties of the final thermopressed specimens. However, the addition of CNF to the pulps (from 2 to 6%) had a further decrease in the dewatering efficiency in the wet-moulding process, and this effect was more pronounced in the Kraft pulp specimens. The mechanical performance of the thermoformed specimens was in the same range as the plastic materials that are conventionally used in food packaging, i.e., modulus 0.6–1.2 GPa, strength 49 MPa and elongation 6–9%. Finally, this study demonstrates the potential of wood pulps to form three-dimensional thermoformed products. Full article

(This article belongs to the Special Issue Nanocellulose: Recent Advances to Unlock Potential for Engineered Sustainable Materials)

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21 pages, 2583 KiB

Open AccessEditor’s ChoiceArticle

The Potentiating Effect of Graphene Oxide on the Arylhydrocarbon Receptor (AhR)–Cytochrome P4501A (Cyp1A) System Activated by Benzo(k)fluoranthene (BkF) in Rainbow Trout Cell Line

by Ana Valdehita, María Luisa Fernández-Cruz and José M. Navas

Nanomaterials 2023, 13(18), 2501; https://doi.org/10.3390/nano13182501 - 5 Sep 2023

Cited by 2 | Viewed by 780

Abstract

The increasing use of graphene oxide (GO) will result in its release into the environment; therefore, it is essential to determine its final fate and possible metabolism by organisms. The objective of this study was to assess the possible role of the aryl [...] Read more.

The increasing use of graphene oxide (GO) will result in its release into the environment; therefore, it is essential to determine its final fate and possible metabolism by organisms. The objective of this study was to assess the possible role of the aryl hydrocarbon receptor (AhR)-dependent cytochrome P4501A (Cyp1A) detoxification activities on the catabolism of GO. Our hypothesis is that GO cannot initially interact with the AhR, but that after an initial degradation caused by other mechanisms, small fractions of GO could activate the AhR, inducing Cyp1A. The environmental pollutant benzo(k)fluoranthene (BkF) was used for the initial activation of the AhR in the rainbow trout (Oncorhynchus mykiss) cell line RTL-W1. Pre-, co-, and post-exposure experiments with GO were performed and Cyp1A induction was monitored. The strong stimulation of Cyp1A observed in cells after exposure to GO, when BkF levels were not detected in the system, suggests a direct action of GO. The role of the AhR was confirmed by a blockage of the observed effects in co-treatment experiments with αNF (an AhR antagonist). These results suggest a possible role for the AhR and Cyp1A system in the cellular metabolism of GO and that GO could modulate the toxicity of environmental pollutants. Full article

(This article belongs to the Special Issue Towards a Safe Nanotechnology: Understanding and Controlling Immunomodulatory and Toxicological Properties of Nanomaterials)

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17 pages, 3529 KiB

Open AccessEditor’s ChoiceArticle

Polyoxometalate-Modified Amphiphilic Polystyrene-block-poly(2-(dimethylamino)ethyl methacrylate) Membranes for Heterogeneous Glucose to Formic Acid Methyl Ester Oxidation

by Yurii Utievskyi, Christof Neumann, Julia Sindlinger, Konstantin Schutjajew, Martin Oschatz, Andrey Turchanin, Nico Ueberschaar and Felix H. Schacher

Nanomaterials 2023, 13(18), 2498; https://doi.org/10.3390/nano13182498 - 5 Sep 2023

Viewed by 849

Abstract

Herein, we present a new heterogeneous catalyst active toward glucose to formic acid methyl ester oxidation. The catalyst was fabricated via electrostatic immobilization of the inorganic polyoxometalate HPA-5 catalyst H₈[PMo₇V₅O₄₀] onto the pore surface of [...] Read more.

Herein, we present a new heterogeneous catalyst active toward glucose to formic acid methyl ester oxidation. The catalyst was fabricated via electrostatic immobilization of the inorganic polyoxometalate HPA-5 catalyst H₈[PMo₇V₅O₄₀] onto the pore surface of amphiphilic block copolymer membranes prepared via non-solvent-induced phase separation (NIPS). The catalyst immobilization was achieved via wet impregnation due to strong coulombic interactions between protonated tertiary amino groups of the polar poly(2-(dimethylamino)ethyl methacrylate) block and the anionic catalyst. Overall, three sets of five consecutive catalytic cycles were performed in an autoclave under 90 °С and 11.5 bar air pressure in methanol, and the corresponding yields of formic acid methyl ester were quantified via head-space gas chromatography. The obtained results demonstrate that the membrane maintains its catalytic activity over multiple cycles, resulting in high to moderate yields in comparison to a homogeneous catalytic system. Nevertheless, presumably due to leaching, the catalytic activity declines over five catalytic cycles. The morphological and chemical changes of the membrane during the prolonged catalysis under harsh conditions were examined in detail using different analytic tools, and it seems that the underlying block copolymer is not affected by the catalytic process. Full article

(This article belongs to the Special Issue Nanoscale Materials and Devices for Electronics, Photonics and Energy Conversion)

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17 pages, 5321 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Adverse Effect of Metallic Gold and Silver Nanoparticles on Xenopus laevis Embryogenesis

by Rosa Carotenuto, Margherita Tussellino, Sabato Fusco, Giovanna Benvenuto, Fabio Formiggini, Bice Avallone, Chiara Maria Motta, Chiara Fogliano and Paolo Antonio Netti

Nanomaterials 2023, 13(17), 2488; https://doi.org/10.3390/nano13172488 - 4 Sep 2023

Viewed by 1035

Abstract

Exposure to metal nanoparticles is potentially harmful, particularly when occurring during embryogenesis. In this study, we tested the effects of commercial AuNPs and AgNPs, widely used in many fields for their features, on the early development of Xenopus laevis, an anuran amphibian [...] Read more.

Exposure to metal nanoparticles is potentially harmful, particularly when occurring during embryogenesis. In this study, we tested the effects of commercial AuNPs and AgNPs, widely used in many fields for their features, on the early development of Xenopus laevis, an anuran amphibian key model species in toxicity testing. Through the Frog Embryo Teratogenesis Assay—Xenopus test (FETAX), we ascertained that both nanoparticles did not influence the survival rate but induced morphological anomalies like modifications of head and branchial arch cartilages, depigmentation of the dorsal area, damage to the intestinal brush border, and heart rate alteration. The expression of genes involved in the early pathways of embryo development was also modified. This study suggests that both types of nanoparticles are toxic though nonlethal, thus indicating that their use requires attention and further study to better clarify their activity in animals and, more importantly, in humans. Full article

(This article belongs to the Special Issue Recent Advances in Metal Nanoparticles and Nanotoxicity)

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14 pages, 2297 KiB

Open AccessEditor’s ChoiceArticle

Sub-Bandgap Sensitization of Perovskite Semiconductors via Colloidal Quantum Dots Incorporation

by G. Ribeiro, G. Ferreira, U. D. Menda, M. Alexandre, M. J. Brites, M. A. Barreiros, S. Jana, H. Águas, R. Martins, P. A. Fernandes, P. Salomé and M. J. Mendes

Nanomaterials 2023, 13(17), 2447; https://doi.org/10.3390/nano13172447 - 29 Aug 2023

Viewed by 1193

Abstract

By taking advantage of the outstanding intrinsic optoelectronic properties of perovskite-based photovoltaic materials, together with the strong near-infrared (NIR) absorption and electronic confinement in PbS quantum dots (QDs), sub-bandgap photocurrent generation is possible, opening the way for solar cell efficiencies surpassing the classical [...] Read more.

By taking advantage of the outstanding intrinsic optoelectronic properties of perovskite-based photovoltaic materials, together with the strong near-infrared (NIR) absorption and electronic confinement in PbS quantum dots (QDs), sub-bandgap photocurrent generation is possible, opening the way for solar cell efficiencies surpassing the classical limits. The present study shows an effective methodology for the inclusion of high densities of colloidal PbS QDs in a MAPbI₃ (methylammonium lead iodide) perovskite matrix as a means to enhance the spectral window of photon absorption of the perovskite host film and allow photocurrent production below its bandgap. The QDs were introduced in the perovskite matrix in different sizes and concentrations to study the formation of quantum-confined levels within the host bandgap and the potential formation of a delocalized intermediate mini-band (IB). Pronounced sub-bandgap (in NIR) absorption was optically confirmed with the introduction of QDs in the perovskite. The consequent photocurrent generation was demonstrated via photoconductivity measurements, which indicated IB establishment in the films. Despite verifying the reduced crystallinity of the MAPbI₃ matrix with a higher concentration and size of the embedded QDs, the nanostructured films showed pronounced enhancement (above 10-fold) in NIR absorption and consequent photocurrent generation at photon energies below the perovskite bandgap. Full article

(This article belongs to the Special Issue Study on Quantum Dot and Quantum Dot-Based Device)

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11 pages, 2930 KiB

Open AccessEditor’s ChoiceArticle

Thermally Stable Ceramic-Salt Electrolytes for Li Metal Batteries Produced from Cold Sintering Using DMF/Water Mixture Solvents

by Sunwoo Kim, Yejin Gim and Wonho Lee

Nanomaterials 2023, 13(17), 2436; https://doi.org/10.3390/nano13172436 - 28 Aug 2023

Viewed by 1217

Abstract

The cold sintering process (CSP) for synthesizing oxide-based electrolytes, which uses water transient solvents and uniaxial pressure, is a promising alternative to the conventional high temperature sintering process due to its low temperature (<200 °C) and short processing time (<2 h). However, the [...] Read more.

The cold sintering process (CSP) for synthesizing oxide-based electrolytes, which uses water transient solvents and uniaxial pressure, is a promising alternative to the conventional high temperature sintering process due to its low temperature (<200 °C) and short processing time (<2 h). However, the formation of amorphous secondary phases in the intergranular regions, which results in poor ionic conductivity (σ), remains a challenge. In this study, we introduced high-boiling solvents of dimethylformamide (DMF, b.p.: 153 °C) and dimethyl sulfoxide (DMSO, b.p.: 189 °C) as transient solvents to develop composite electrolytes of Li₁.₅Al₀.₅Ge₁.₅(PO₄)₃ (LAGP) with bis(trifluoromethane)sulfonimide lithium salt (LiTFSI). Our results show that composite electrolytes processed with the DMF/water mixture (CSP LAGP-LiTFSI DMF/H₂O) yield a high σ of 10⁻⁴ S cm⁻¹ at room temperature and high relative densities of >87%. Furthermore, the composite electrolytes exhibit good thermal stability; the σ maintains its initial value after heat treatment. In contrast, the composite electrolytes processed with the DMSO/water mixture and water alone show thermal degradation. The CSP LAGP-LiTFSI DMF/H₂O composite electrolytes exhibit long-term stability, showing no signs of short circuiting after 350 h at 0.1 mAh cm⁻² in Li symmetric cells. Our work highlights the importance of selecting appropriate transient solvents for producing efficient and stable composite electrolytes using CSP. Full article

(This article belongs to the Special Issue Nanocomposites for Energy Harvesting)

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10 pages, 2807 KiB

Open AccessEditor’s ChoiceArticle

Sol–Gel-Processed Y₂O₃ Multilevel Resistive Random-Access Memory Cells for Neural Networks

by Taehun Lee, Hae-In Kim, Yoonjin Cho, Sangwoo Lee, Won-Yong Lee, Jin-Hyuk Bae, In-Man Kang, Kwangeun Kim, Sin-Hyung Lee and Jaewon Jang

Nanomaterials 2023, 13(17), 2432; https://doi.org/10.3390/nano13172432 - 27 Aug 2023

Cited by 1 | Viewed by 1049

Abstract

Yttrium oxide (Y₂O₃) resistive random-access memory (RRAM) devices were fabricated using the sol–gel process on indium tin oxide/glass substrates. These devices exhibited conventional bipolar RRAM characteristics without requiring a high-voltage forming process. The effect of current compliance on the [...] Read more.

Yttrium oxide (Y₂O₃) resistive random-access memory (RRAM) devices were fabricated using the sol–gel process on indium tin oxide/glass substrates. These devices exhibited conventional bipolar RRAM characteristics without requiring a high-voltage forming process. The effect of current compliance on the Y₂O₃ RRAM devices was investigated, and the results revealed that the resistance values gradually decreased with increasing set current compliance values. By regulating these values, the formation of pure Ag conductive filament could be restricted. The dominant oxygen ion diffusion and migration within Y₂O₃ leads to the formation of oxygen vacancies and Ag metal-mixed conductive filaments between the two electrodes. The filament composition changes from pure Ag metal to Ag metal mixed with oxygen vacancies, which is crucial for realizing multilevel cell (MLC) switching. Consequently, intermediate resistance values were obtained, which were suitable for MLC switching. The fabricated Y₂O₃ RRAM devices could function as a MLC with a capacity of two bits in one cell, utilizing three low-resistance states and one common high-resistance state. The potential of the Y₂O₃ RRAM devices for neural networks was further explored through numerical simulations. Hardware neural networks based on the Y₂O₃ RRAM devices demonstrated effective digit image classification with a high accuracy rate of approximately 88%, comparable to the ideal software-based classification (~92%). This indicates that the proposed RRAM can be utilized as a memory component in practical neuromorphic systems. Full article

(This article belongs to the Special Issue Nanostructures for Integrated Devices)

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23 pages, 5403 KiB

Open AccessEditor’s ChoiceArticle

Novel Microemulsions with Essential Oils for Environmentally Friendly Cleaning of Copper Cultural Heritage Artifacts

by Mihaela Ioan, Dan Florin Anghel, Ioana Catalina Gifu, Elvira Alexandrescu, Cristian Petcu, Lia Mara Diţu, Georgiana Alexandra Sanda, Daniela Bala and Ludmila Otilia Cinteza

Nanomaterials 2023, 13(17), 2430; https://doi.org/10.3390/nano13172430 - 26 Aug 2023

Cited by 1 | Viewed by 2096

Abstract

Cleaning represents an important and challenging operation in the conservation of cultural heritage, and at present, a key issue consists in the development of more sustainable, “green” materials and methods to perform it. In the present work, a novel xylene-in-water microemulsion based on [...] Read more.

Cleaning represents an important and challenging operation in the conservation of cultural heritage, and at present, a key issue consists in the development of more sustainable, “green” materials and methods to perform it. In the present work, a novel xylene-in-water microemulsion based on nonionic surfactants with low toxicity was obtained, designed as low-impact cleaning agent for metallic historic objects. Phase diagram of the mixtures containing polyoxyethylene-polyoxypropilene triblock copolymer Pluronic P84 and D-alpha-tocopheryl polyethylene glycol 1000 succinate (TPGS) as surfactants, water, ethanol and xylene was studied, and a microemulsion with low surfactant content was selected as suitable cleaning nanosystem. Essential oils (EOs) from thyme and cinnamon leaf were added to the selected microemulsion in order to include other beneficial properties such as anticorrosive and antifungal protection. The microemulsions with or without EOs were characterized by size, size distribution and zeta potential. The cleaning efficacy of the tested microemulsions was assessed based on their ability to remove two types of artificial dirt by using X-ray energy dispersion spectrometry (EDX), scanning electron microscopy (SEM), contact angle measurements and color analysis. Microemulsions exhibit high capacity to remove artificial dirt from model copper coupons in spite of very low content of the organic solvent. Both thyme and cinnamon oil loading microemulsions prove to significantly reduce the corrosion rate of treated metallic plates compared to those of bare copper. The antifungal activity of the novel type of microemulsion was evaluated against Aspergillus niger, reported as main treat in biocorrosion of historic copper artifacts. Application of microemulsion with small amounts of EOs on Cu plates inhibits the growth of fungi, providing a good fungicidal effect. Full article

(This article belongs to the Special Issue Micro/Nano Emulsions: Fabrication and Applications)

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22 pages, 6250 KiB

Open AccessEditor’s ChoiceArticle

Mesoporous Dual-Semiconductor ZnS/CdS Nanocomposites as Efficient Visible Light Photocatalysts for Hydrogen Generation

by Ioannis Vamvasakis, Evangelos K. Andreou and Gerasimos S. Armatas

Nanomaterials 2023, 13(17), 2426; https://doi.org/10.3390/nano13172426 - 26 Aug 2023

Cited by 1 | Viewed by 1351

Abstract

The development of functional catalysts for the photogeneration of hydrogen (H₂) via water-splitting is crucial in the pursuit of sustainable energy solutions. To that end, metal-sulfide semiconductors, such as CdS and ZnS, can play a significant role in the process due [...] Read more.

The development of functional catalysts for the photogeneration of hydrogen (H₂) via water-splitting is crucial in the pursuit of sustainable energy solutions. To that end, metal-sulfide semiconductors, such as CdS and ZnS, can play a significant role in the process due to their interesting optoelectronic and catalytic properties. However, inefficient charge-carrier dissociation and poor photochemical stability remain significant limitations to photocatalytic efficiency. Herein, dual-semiconductor nanocomposites of ZnS/CdS nanocrystal assemblies (NCAs) are developed as efficient visible light photocatalysts for H₂ generation. The resultant materials, synthesized via a polymer-templated self-polymerization method, comprise a unique combination of ~5–7 nm-sized metal-sulfide nanoparticles that are interlinked to form a 3D open-pore structure with large internal surface area (up to 285 m² g⁻¹) and uniform pores (circa 6–7 nm). By adjusting the ratio of constituent nanoparticles, the optimized ZnS/CdS catalyst with 50 wt.% ZnS content demonstrates a remarkable stability and visible light H₂-evolution activity (~29 mmol g⁻¹ h⁻¹ mass activity) with an apparent quantum yield (AQY) of 60% at 420 nm. Photocatalytic evaluation experiments combined with electrochemical and spectroscopic studies suggest that the superior photocatalytic performance of these materials stems from the accessible 3D open-pore structure and the efficient defect-mediated charge transfer mechanism at the ZnS/CdS nanointerfaces. Overall, this work provides a new perspective for designing functional and stable photocatalytic materials for sustainable H₂ production. Full article

(This article belongs to the Special Issue Early-Career Researchers in Environmental Nanoscience and Nanotechnology)

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14 pages, 4968 KiB

Open AccessEditor’s ChoiceArticle

Nanostructured Carbon-Doped BN for CO₂ Capture Applications

by Rimeh Mighri, Kevin Turani-I-Belloto, Umit B. Demirci and Johan G. Alauzun

Nanomaterials 2023, 13(17), 2389; https://doi.org/10.3390/nano13172389 - 22 Aug 2023

Viewed by 895

Abstract

Carbon-doped boron nitride (denoted by BN/C) was prepared through the pyrolysis at 1100 °C of a nanostructured mixture of an alkyl amine borane adduct and ammonia borane. The alkyl amine borane adduct acts as a soft template to obtain nanospheres. This bottom-up approach [...] Read more.

Carbon-doped boron nitride (denoted by BN/C) was prepared through the pyrolysis at 1100 °C of a nanostructured mixture of an alkyl amine borane adduct and ammonia borane. The alkyl amine borane adduct acts as a soft template to obtain nanospheres. This bottom-up approach for the synthesis of nanostructured BN/C is relatively simple and compelling. It allows the structure obtained during the emulsion process to be kept. The final BN/C materials are microporous, with interconnected pores in the nanometer range (0.8 nm), a large specific surface area of up to 767 m²·g⁻¹ and a pore volume of 0.32 cm³·g⁻¹. The gas sorption studied with CO₂ demonstrated an appealing uptake of 3.43 mmol·g⁻¹ at 0 °C, a high CO₂/N₂ selectivity (21) and 99% recyclability after up to five adsorption–desorption cycles. Full article

(This article belongs to the Special Issue Advanced Nanomaterials for Gas Capture, Separation and Storage)

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27 pages, 9166 KiB

Open AccessEditor’s ChoiceReview

Tin/Tin Oxide Nanostructures: Formation, Application, and Atomic and Electronic Structure Peculiarities

by Poting Liu and Vladimir Sivakov

Nanomaterials 2023, 13(17), 2391; https://doi.org/10.3390/nano13172391 - 22 Aug 2023

Cited by 2 | Viewed by 2109

Abstract

For a very long period, tin was considered one of the most important metals for humans due to its easy access in nature and abundance of sources. In the past, tin was mainly used to make various utensils and weapons. Today, nanostructured tin [...] Read more.

For a very long period, tin was considered one of the most important metals for humans due to its easy access in nature and abundance of sources. In the past, tin was mainly used to make various utensils and weapons. Today, nanostructured tin and especially its oxide materials have been found to possess many characteristic physical and chemical properties that allow their use as functional materials in various fields such as energy storage, photocatalytic process, gas sensors, and solar cells. This review discusses current methods for the synthesis of Sn/SnO₂ composite materials in form of powder or thin film, as well as the application of the most advanced characterization tools based on large-scale synchrotron radiation facilities to study their chemical composition and electronic features. In addition, the applications of Sn/SnO₂ composites in various fields are presented in detail. Full article

(This article belongs to the Special Issue Current Review in Nanofabrication and Nanomanufacturing)

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17 pages, 3641 KiB

Open AccessEditor’s ChoiceArticle

Low-Temperature Emission Dynamics of Methylammonium Lead Bromide Hybrid Perovskite Thin Films at the Sub-Micrometer Scale

by Justine Baronnier, Benoit Mahler, Christophe Dujardin and Julien Houel

Nanomaterials 2023, 13(16), 2376; https://doi.org/10.3390/nano13162376 - 19 Aug 2023

Cited by 1 | Viewed by 8300

Abstract

We study the low-temperature (T = 4.7 K) emission dynamics of a thin film of methylammonium lead bromide (MAPbBr

_{3}

), prepared via the anti-solvent method. Using intensity-dependent (over 5 decades) hyperspectral microscopy under quasi-resonant (532 nm) continuous wave excitation, we revealed spatial [...] Read more.

We study the low-temperature (T = 4.7 K) emission dynamics of a thin film of methylammonium lead bromide (MAPbBr

_{3}

), prepared via the anti-solvent method. Using intensity-dependent (over 5 decades) hyperspectral microscopy under quasi-resonant (532 nm) continuous wave excitation, we revealed spatial inhomogeneities in the thin film emission. This was drastically different at the band-edge (∼550 nm, sharp peaks) than in the emission tail (∼568 nm, continuum of emission). We are able to observe regions of the film at the micrometer scale where emission is dominated by excitons, in between regions of trap emission. Varying the density of absorbed photons by the MAPbBr

_{3}

thin films, two-color fluorescence lifetime imaging microscopy unraveled the emission dynamics: a fast, resolution-limited (∼200 ps) monoexponential tangled with a stretched exponential decay. We associate the first to the relaxation of excitons and the latter to trap emission dynamics. The obtained stretching exponents can be interpreted as the result of a two-dimensional electron diffusion process: Förster resonant transfer mechanism. Furthermore, the non-vanishing fast monoexponential component even in the tail of the MAPbBr

_{3}

emission indicates the subsistence of localized excitons. Finally, we estimate the density of traps in MAPbBr

_{3}

thin films prepared using the anti-solvent method at n∼10

^{17}

cm

^{- 3}

. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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18 pages, 7214 KiB

Open AccessEditor’s ChoiceArticle

A Combined Plasmonic and Electrochemical Aptasensor Based on Gold Nanopit Arrays for the Detection of Human Serum Albumin

by Ruifeng Zhu, Gabriela Figueroa-Miranda, Lei Zhou, Ziheng Hu, Bohdan Lenyk, Sven Ingebrandt, Andreas Offenhäusser and Dirk Mayer

Nanomaterials 2023, 13(16), 2374; https://doi.org/10.3390/nano13162374 - 19 Aug 2023

Viewed by 1053

Abstract

Electrochemical and optical platforms are commonly employed in designing biosensors. However, one signal readout can easily lead to inaccuracies due to the effect of nonstandard test procedures, different operators, and experimental environments. We have developed a dual-signal protocol that combined two transducer principles [...] Read more.

Electrochemical and optical platforms are commonly employed in designing biosensors. However, one signal readout can easily lead to inaccuracies due to the effect of nonstandard test procedures, different operators, and experimental environments. We have developed a dual-signal protocol that combined two transducer principles in one aptamer-based biosensor by simultaneously performing electrochemical- and extraordinary optical transmission (EOT)-based plasmonic detection using gold nanopit arrays (AuNpA). Compared with full hole structures, we found that nanopits, that did not fully penetrate the gold film, not only exhibited a better plasmonic bandwidth and refractive index sensitivity both in the finite-difference time-domain simulation and in experiments by shielding the gold/quartz mode but also enlarged the electrochemical active surface area. Therefore, the periodic non-fully penetrating AuNpA were modified with ferrocene-labeled human serum albumin aptamer receptors. The formation of the receptor layer and human serum albumin binding complex induced a conformational change, which resulted in variation in the electron transfer between the electro-active ferrocene units and the AuNpA surface. Simultaneously, the binding event caused a surface plasmon polaritons wavelength shift corresponding to a change in the surface refractive index. Interestingly, although both transducers recorded the same binding process, they led to different limits of detection, dynamic ranges, and sensitivities. The electrochemical transducer showed a dynamic detection range from 1 nM to 600

μ

M, while the optical transducer covered high concentrations from 100

μ

M to 600

μ

M. This study not only provides new insights into the design of plasmonic nanostructures but also potentially opens an exciting avenue for dual-signal disease diagnosis and point-of-care testing applications. Full article

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12 pages, 2957 KiB

Open AccessEditor’s ChoiceArticle

Doping-Free Phosphorescent and Thermally Activated Delayed Fluorescent Organic Light-Emitting Diodes with an Ultra-Thin Emission Layer

by Eun-Bi Jang, Geun-Su Choi, Eun-Jeong Bae, Byeong-Kwon Ju and Young-Wook Park

Nanomaterials 2023, 13(16), 2366; https://doi.org/10.3390/nano13162366 - 18 Aug 2023

Viewed by 1468

Abstract

We report the electroluminescence (EL) characteristics of blue ultra-thin emissive layer (U-EML) phosphorescent (PH) organic light-emitting diodes (OLED) and thermally activated delayed fluorescence (TADF) OLED. A variety of transport layer (TL) materials were used in the fabricated OLEDs. The well-known FIrpic and DMAC-DPS [...] Read more.

We report the electroluminescence (EL) characteristics of blue ultra-thin emissive layer (U-EML) phosphorescent (PH) organic light-emitting diodes (OLED) and thermally activated delayed fluorescence (TADF) OLED. A variety of transport layer (TL) materials were used in the fabricated OLEDs. The well-known FIrpic and DMAC-DPS were used with a thickness of 0.3 nm, which is relatively thicker than the optimal thickness (0.15 nm) of the blue phosphorescent ultra-thin emissive layer to ensure sufficient energy transfer. While FIrpic showed overall high efficiency in various TLs, DMAC-DPS exhibited three times lower efficiency in limited TLs. To clarify/identify low efficiency and to improve the EL, the thickness of DMAC-DPS was varied. A significantly higher and comparable efficiency was observed with a thickness of 4.5 nm, which is 15 times thicker. This thickness was oriented from the TADF itself, which reduces quenching in a triplet–triplet annihilation compared to the PH process. The thinner optimal thickness compared with ~30 nm of fluorescent OLEDs suggests that there still is quenching taking place. We expect that the efficiency of TADF U-EML OLEDs can be enhanced through further research on controlling the exciton quenching using multiple U-EMLs with spacers and a novel material with a high energy transfer rate (ΔE_S-T). Full article

(This article belongs to the Special Issue Multifunctional Materials and Applications: Basic Nanomaterials, Catalysis, Composite, Electronic and Biomaterials)

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18 pages, 4737 KiB

Open AccessEditor’s ChoiceArticle

Biosensor Based on Graphene Directly Grown by MW-PECVD for Detection of COVID-19 Spike (S) Protein and Its Entry Receptor ACE2

by Šarunas Meškinis, Rimantas Gudaitis, Andrius Vasiliauskas, Asta Guobienė, Šarūnas Jankauskas, Voitech Stankevič, Skirmantas Keršulis, Arūnas Stirkė, Eivydas Andriukonis, Wanessa Melo, Vilius Vertelis and Nerija Žurauskienė

Nanomaterials 2023, 13(16), 2373; https://doi.org/10.3390/nano13162373 - 18 Aug 2023

Cited by 1 | Viewed by 1346

Abstract

Biosensors based on graphene field-effect transistors (G-FET) for detecting COVID-19 spike S protein and its receptor ACE2 were reported. The graphene, directly synthesized on SiO₂/Si substrate by microwave plasma-enhanced chemical vapor deposition (MW-PECVD), was used for FET biosensor fabrication. The commercial [...] Read more.

Biosensors based on graphene field-effect transistors (G-FET) for detecting COVID-19 spike S protein and its receptor ACE2 were reported. The graphene, directly synthesized on SiO₂/Si substrate by microwave plasma-enhanced chemical vapor deposition (MW-PECVD), was used for FET biosensor fabrication. The commercial graphene, CVD-grown on a copper substrate and subsequently transferred onto a glass substrate, was applied for comparison purposes. The graphene structure and surface morphology were studied by Raman scattering spectroscopy and atomic force microscope. Graphene surfaces were functionalized by an aromatic molecule PBASE (1-pyrenebutanoic acid succinimidyl ester), and subsequent immobilization of the receptor angiotensin-converting enzyme 2 (ACE2) was performed. A microfluidic system was developed, and transfer curves of liquid-gated FET were measured after each graphene surface modification procedure to investigate ACE2 immobilization by varying its concentration and subsequent spike S protein detection. The directly synthesized graphene FET sensitivity to the receptor ACE2, evaluated in terms of the Dirac voltage shift, exceeded the sensitivity of the transferred commercial graphene-based FET. The concentration of the spike S protein was detected in the range of 10 ag/mL up to 10 μg/mL by using a developed microfluidic system and measuring the transfer characteristics of the liquid-gated G-FETs. It was found that the shift of the Dirac voltage depends on the spike S concentration and was 27 mV with saturation at 10 pg/mL for directly synthesized G-FET biosensor, while for transferred G-FET, the maximal shift of 70 mV was obtained at 10 μg/mL with a tendency of saturation at 10 ng/mL. The detection limit as low as 10 ag/mL was achieved for both G-FETs. The sensitivity of the biosensors at spike S concentration of 10 pg/mL measured as relative current change at a constant gate voltage corresponding to the highest transconductance of the G-FETs was found at 5.6% and 8.8% for directly synthesized and transferred graphene biosensors, respectively. Thus, MW-PECVD-synthesized graphene-based biosensor demonstrating high sensitivity and low detection limit has excellent potential for applications in COVID-19 diagnostics. Full article

(This article belongs to the Special Issue Vapor-Based Graphene Synthesis and Its Applications)

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14 pages, 3082 KiB

Open AccessEditor’s ChoiceArticle

Stabilization of Beeswax-In-Water Dispersions Using Anionic Cellulose Nanofibers and Their Application in Paper Coating

by Genís Bayés, Roberto J. Aguado, Quim Tarrés, Jaume Planella and Marc Delgado-Aguilar

Nanomaterials 2023, 13(16), 2353; https://doi.org/10.3390/nano13162353 - 16 Aug 2023

Viewed by 1208

Abstract

Beeswax is a bio-sourced, renewable, and even edible material that stands as a convincing option to provide paper-based food packaging with moisture resistance. Nonetheless, the difficulty of dispersing it in water limits its applicability. This work uses oxidized, negatively charged cellulose nanofibers along [...] Read more.

Beeswax is a bio-sourced, renewable, and even edible material that stands as a convincing option to provide paper-based food packaging with moisture resistance. Nonetheless, the difficulty of dispersing it in water limits its applicability. This work uses oxidized, negatively charged cellulose nanofibers along with glycerol to stabilize beeswax-in-water emulsions above the melting point of the wax. The synergistic effects of nanocellulose and glycerol granted the stability of the dispersion even when it cooled down, but only if the concentration of nanofibers was high enough. This required concentration (0.6–0.9 wt%) depended on the degree of oxidation of the cellulose nanofibers. Rheological hindrance was essential to prevent the buoyancy of beeswax particles, while the presence of glycerol prevented excessive aggregation. The mixtures had yield stress and showed pseudoplastic behavior at a high enough shear rate, with their apparent viscosity being positively influenced by the surface charge density of the nanofibers. When applied to packaging paper, the nanocellulose-stabilized beeswax suspensions not only enhanced its barrier properties towards liquid water (reaching a contact angle of 96°) and water vapor (<100 g m⁻² d⁻¹), but also to grease (Kit rating: 5) and airflow (>1400 Gurley s). While falling short of polyethylene-coated paper, this overall improvement, attained using only one layer of a biobased coating suspension, should be understood as a step towards replacing synthetic waxes and plastic laminates. Full article

(This article belongs to the Special Issue Nanocellulose: Recent Advances to Unlock Potential for Engineered Sustainable Materials)

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21 pages, 5449 KiB

Open AccessEditor’s ChoiceArticle

Synthesis of Aluminum-Based Metal–Organic Framework (MOF)-Derived Carbon Nanomaterials and Their Water Adsorption Isotherm

by Dasom Jeong, Seong Cheon Kim, Taeseop An, Dongho Lee, Haejin Hwang, Siyoung Q. Choi and Jeasung Park

Nanomaterials 2023, 13(16), 2351; https://doi.org/10.3390/nano13162351 - 16 Aug 2023

Cited by 1 | Viewed by 1621

Abstract

The characteristics of water vapor adsorption depend on the structure, porosity, and functional groups of the material. Metal–organic framework (MOF)-derived carbon (MDC) is a novel material that exhibits a high specific area and tunable pore sizes by exploiting the stable structure and porosity [...] Read more.

The characteristics of water vapor adsorption depend on the structure, porosity, and functional groups of the material. Metal–organic framework (MOF)-derived carbon (MDC) is a novel material that exhibits a high specific area and tunable pore sizes by exploiting the stable structure and porosity of pure MOF materials. Herein, two types of aluminum-based MOFs were used as precursors to synthesize hydrophobic microporous C-MDC and micro-mesoporous A-MDC via carbonization and activation depending on the type of ligands in the precursors. C-MDC and A-MDC have different pore characteristics and exhibit distinct water adsorption properties. C-MDC with hydrophobic properties and micropores exhibited negligible water adsorption (108.54 mgg⁻¹) at relatively low pressures (P/P₀~0.3) but showed a rapid increase in water adsorption ability (475.7 mgg⁻¹) at relative pressures of about 0.6. A comparison with the isotherm model indicated that the results were consistent with the theories, which include site filling at low relative pressure and pore filling at high relative pressure. In particular, the Do–Do model specialized for type 5 showed excellent agreement. Full article

(This article belongs to the Special Issue Metal Organic Framework (MOF)-Based Micro/Nanoscale Materials)

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30 pages, 6695 KiB

Open AccessEditor’s ChoiceArticle

Microemulsions of Nonionic Surfactant with Water and Various Homologous Esters: Preparation, Phase Transitions, Physical Property Measurements, and Application for Extraction of Tricyclic Antidepressant Drugs from Aqueous Media

by Radu C. Racovita, Maria D. Ciuca, Daniela Catana, Cezar Comanescu and Oana Ciocirlan

Nanomaterials 2023, 13(16), 2311; https://doi.org/10.3390/nano13162311 - 11 Aug 2023

Cited by 2 | Viewed by 1626

Abstract

Microemulsions are nanocolloidal systems composed of water, an oil, and a surfactant, sometimes with an additional co-surfactant, which have found a wide range of practical applications, including the extractive removal of contaminants from polluted water. In this study, microemulsion systems, including a nonionic [...] Read more.

Microemulsions are nanocolloidal systems composed of water, an oil, and a surfactant, sometimes with an additional co-surfactant, which have found a wide range of practical applications, including the extractive removal of contaminants from polluted water. In this study, microemulsion systems, including a nonionic surfactant (Brij 30), water, and esters selected from two homologous series of C₁–C₆ alkyl acetates and ethyl C₁–C₄ carboxylates, respectively, were prepared by the surfactant titration method. Phase transitions leading to the formation of Winsor II and Winsor IV microemulsions were observed and phase diagrams were constructed. The dependences of phase transitions on the salinity and pH and the addition of isopropanol as a co-surfactant were also investigated. Some physical properties, namely density, refractive index, electrical conductivity, dynamic viscosity, and particle size, were measured for a selection of Winsor IV microemulsions, providing further insight into some other phase transitions occurring in the monophasic domains of phase diagrams. Finally, Winsor II microemulsions were tested as extraction solvents for the removal of four tricyclic antidepressant drugs from aqueous media. Propyl acetate/Brij 30/H₂O microemulsions provided the best extraction yields (>90%), the highest Nernst distribution coefficients (~40–88), and a large volumetric ratio of almost 3 between the recovered purified water and the resulting microemulsion extract. Increasing the ionic strength (salinity) or the pH of the aqueous antidepressant solutions led to an improvement in extraction efficiencies, approaching 100%. These results could be extrapolated to other classes of pharmaceutical contaminants and suggest ester- and nonionic surfactant-based microemulsions are a promising tool for environmental remediation. Full article

(This article belongs to the Special Issue Micro/Nano Emulsions: Fabrication and Applications)

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18 pages, 3129 KiB

Open AccessEditor’s ChoiceArticle

Hydrothermal Transformation of Eggshell Calcium Carbonate into Apatite Micro-Nanoparticles: Cytocompatibility and Osteoinductive Properties

by Adriana Torres-Mansilla, Pedro Álvarez-Lloret, Raquel Fernández-Penas, Annarita D’Urso, Paula Alejandra Baldión, Francesca Oltolina, Antonia Follenzi and Jaime Gómez-Morales

Nanomaterials 2023, 13(16), 2299; https://doi.org/10.3390/nano13162299 - 10 Aug 2023

Viewed by 1790

Abstract

The eggshell is a biomineral consisting of CaCO₃ in the form of calcite phase and a pervading organic matrix (1–3.5 wt.%). Transforming eggshell calcite particles into calcium phosphate (apatite) micro-nanoparticles opens the door to repurposing the eggshell waste as materials with potential [...] Read more.

The eggshell is a biomineral consisting of CaCO₃ in the form of calcite phase and a pervading organic matrix (1–3.5 wt.%). Transforming eggshell calcite particles into calcium phosphate (apatite) micro-nanoparticles opens the door to repurposing the eggshell waste as materials with potential biomedical applications, fulfilling the principles of the circular economy. Previous methods to obtain these particles consisted mainly of two steps, the first one involving the calcination of the eggshell. In this research, direct transformation by a one-pot hydrothermal method ranging from 100–200 °C was studied, using suspensions with a stoichiometric P/CaCO₃ ratio, K₂HPO₄ as P reagent, and eggshells particles (Ø < 50 μm) both untreated and treated with NaClO to remove surface organic matter. In the untreated group, the complete conversion was achieved at 160 °C, and most particles displayed a hexagonal plate morphology, eventually with a central hole. In the treated group, this replacement occurred at 180 °C, yielding granular (spherulitic) apatite nanoparticles. The eggshell particles and apatite micro-nanoparticles were cytocompatible when incubated with MG-63 human osteosarcoma cells and m17.ASC murine mesenchymal stem cells and promoted the osteogenic differentiation of m17.ASC cells. The study results are useful for designing and fabricating biocompatible microstructured materials with osteoinductive properties for applications in bone tissue engineering and dentistry. Full article

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13 pages, 5256 KiB

Open AccessEditor’s ChoiceArticle

Over- and Undercoordinated Atoms as a Source of Electron and Hole Traps in Amorphous Silicon Nitride (a-Si₃N₄)

by Christoph Wilhelmer, Dominic Waldhoer, Lukas Cvitkovich, Diego Milardovich, Michael Waltl and Tibor Grasser

Nanomaterials 2023, 13(16), 2286; https://doi.org/10.3390/nano13162286 - 9 Aug 2023

Cited by 2 | Viewed by 1182

Abstract

Silicon nitride films are widely used as the charge storage layer of charge trap flash (CTF) devices due to their high charge trap densities. The nature of the charge trapping sites in these materials responsible for the memory effect in CTF devices is [...] Read more.

Silicon nitride films are widely used as the charge storage layer of charge trap flash (CTF) devices due to their high charge trap densities. The nature of the charge trapping sites in these materials responsible for the memory effect in CTF devices is still unclear. Most prominently, the Si dangling bond or K-center has been identified as an amphoteric trap center. Nevertheless, experiments have shown that these dangling bonds only make up a small portion of the total density of electrical active defects, motivating the search for other charge trapping sites. Here, we use a machine-learned force field to create model structures of amorphous Si

_{3}

N

_{4}

by simulating a melt-and-quench procedure with a molecular dynamics algorithm. Subsequently, we employ density functional theory in conjunction with a hybrid functional to investigate the structural properties and electronic states of our model structures. We show that electrons and holes can localize near over- and under-coordinated atoms, thereby introducing defect states in the band gap after structural relaxation. We analyze these trapping sites within a nonradiative multi-phonon model by calculating relaxation energies and thermodynamic charge transition levels. The resulting defect parameters are used to model the potential energy curves of the defect systems in different charge states and to extract the classical energy barrier for charge transfer. The high energy barriers for charge emission compared to the vanishing barriers for charge capture at the defect sites show that intrinsic electron traps can contribute to the memory effect in charge trap flash devices. Full article

(This article belongs to the Special Issue Nanoscale Science and Technology on Semiconductor Device Physics)

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33 pages, 3912 KiB

Open AccessEditor’s ChoiceReview

Advanced Bioactive Glasses: The Newest Achievements and Breakthroughs in the Area

by Maroua H. Kaou, Mónika Furkó, Katalin Balázsi and Csaba Balázsi

Nanomaterials 2023, 13(16), 2287; https://doi.org/10.3390/nano13162287 - 9 Aug 2023

Cited by 6 | Viewed by 3054

Abstract

Bioactive glasses (BGs) are especially useful materials in soft and bone tissue engineering and even in dentistry. They can be the solution to many medical problems, and they have a huge role in the healing processes of bone fractures. Interestingly, they can also [...] Read more.

Bioactive glasses (BGs) are especially useful materials in soft and bone tissue engineering and even in dentistry. They can be the solution to many medical problems, and they have a huge role in the healing processes of bone fractures. Interestingly, they can also promote skin regeneration and wound healing. Bioactive glasses are able to attach to the bone tissues and form an apatite layer which further initiates the biomineralization process. The formed intermediate apatite layer makes a connection between the hard tissue and the bioactive glass material which results in faster healing without any complications or side effects. This review paper summarizes the most recent advancement in the preparation of diverse types of BGs, such as silicate-, borate- and phosphate-based bioactive glasses. We discuss their physical, chemical, and mechanical properties detailing how they affect their biological performances. In order to get a deeper insight into the state-of-the-art in this area, we also consider their medical applications, such as bone regeneration, wound care, and dental/bone implant coatings. Full article

(This article belongs to the Special Issue Bioactive Nanomaterials for Modern Biotechnological Applications)

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12 pages, 3655 KiB

Open AccessEditor’s ChoiceArticle

The Effect of Nanobubble Water Containing Cordyceps Extract and Withaferin A on Free Fatty Acid-Induced Lipid Accumulation in HepG2 Cells

by Hanlin Han, Yixin Sun, Weixu Zhang, Zhenya Zhang and Tian Yuan

Nanomaterials 2023, 13(15), 2265; https://doi.org/10.3390/nano13152265 - 7 Aug 2023

Viewed by 1045

Abstract

Cordyceps extract and withaferin A (Wi-A) are natural compounds that have therapeutic effects on non-alcoholic fatty liver disease (NAFLD). However, their efficacy is limited and a long treatment duration is usually required. To enhance their efficiency, the synergistic effects of nanobubble water (NBW) [...] Read more.

Cordyceps extract and withaferin A (Wi-A) are natural compounds that have therapeutic effects on non-alcoholic fatty liver disease (NAFLD). However, their efficacy is limited and a long treatment duration is usually required. To enhance their efficiency, the synergistic effects of nanobubble water (NBW) derived from nitrogen, hydrogen, and oxygen gases were investigated. Results showed that the physical properties of all three NBWs, including nanobubble density (10⁸ particles/mL) and zeta potential (below −22 mV), were stable during 48 h of storage. Hydrogen and nitrogen NBWs did not reduce, but instead promoted, free fatty acid-induced lipid accumulation in HepG2 cells. In contrast, oxygen NBW synergistically enhanced the effects of cordyceps extract and Wi-A. The lipid content decreased by 29% and 33% in the oxygen NBW + cordyceps extract and oxygen NBW + Wi-A groups, respectively, compared to reductions of 22% and 16% by aqueous extracts without NB. This study found that NBW may enhance the lipid-reducing effects of natural compounds, such as cordyceps extract and withaferin A, in hepatic cells. Further studies in animal experiments are needed to determine whether NBW has a potential application in NAFLD. Full article

(This article belongs to the Special Issue Micro/Nanobubbles for Biomedical Applications)

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20 pages, 20699 KiB

Open AccessEditor’s ChoiceArticle

Biomolecular Adsorprion at ZnS Nanomaterials: A Molecular Dynamics Simulation Study of the Adsorption Preferences, Effects of the Surface Curvature and Coating

by Roja Rahmani and Alexander P. Lyubartsev

Nanomaterials 2023, 13(15), 2239; https://doi.org/10.3390/nano13152239 - 2 Aug 2023

Cited by 2 | Viewed by 1067

Abstract

The understanding of interactions between nanomaterials and biological molecules is of primary importance for biomedical applications of nanomaterials, as well as for the evaluation of their possible toxic effects. Here, we carried out extensive molecular dynamics simulations of the adsorption properties of about [...] Read more.

The understanding of interactions between nanomaterials and biological molecules is of primary importance for biomedical applications of nanomaterials, as well as for the evaluation of their possible toxic effects. Here, we carried out extensive molecular dynamics simulations of the adsorption properties of about 30 small molecules representing biomolecular fragments at ZnS surfaces in aqueous media. We computed adsorption free energies and potentials of mean force of amino acid side chain analogs, lipids, and sugar fragments to ZnS (110) crystal surface and to a spherical ZnS nanoparticle. Furthermore, we investigated the effect of poly-methylmethacrylate (PMMA) coating on the adsorption preferences of biomolecules to ZnS. We found that only a few anionic molecules: aspartic and glutamic acids side chains, as well as the anionic form of cysteine show significant binding to pristine ZnS surface, while other molecules show weak or no binding. Spherical ZnS nanoparticles show stronger binding of these molecules due to binding at the edges between different surface facets. Coating of ZnS by PMMA changes binding preferences drastically: the molecules that adsorb to a pristine ZnS surface do not adsorb on PMMA-coated surfaces, while some others, particularly hydrophobic or aromatic amino-acids, show high binding affinity due to binding to the coating. We investigate further the hydration properties of the ZnS surface and relate them to the binding preferences of biomolecules. Full article

(This article belongs to the Section Theory and Simulation of Nanostructures)

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19 pages, 3494 KiB

Open AccessFeature PaperEditor’s ChoiceArticle

Hard-Shelled Glycol Chitosan Nanoparticles for Dual MRI/US Detection of Drug Delivery/Release: A Proof-of-Concept Study

by Simona Baroni, Monica Argenziano, Francesca La Cava, Marco Soster, Francesca Garello, David Lembo, Roberta Cavalli and Enzo Terreno

Nanomaterials 2023, 13(15), 2227; https://doi.org/10.3390/nano13152227 - 1 Aug 2023

Cited by 3 | Viewed by 979

Abstract

This paper describes a novel nanoformulation for dual MRI/US in vivo monitoring of drug delivery/release. The nanosystem was made of a perfluoropentane core coated with phospholipids stabilized by glycol chitosan crosslinked with triphosphate ions, and it was co-loaded with the prodrug prednisolone phosphate [...] Read more.

This paper describes a novel nanoformulation for dual MRI/US in vivo monitoring of drug delivery/release. The nanosystem was made of a perfluoropentane core coated with phospholipids stabilized by glycol chitosan crosslinked with triphosphate ions, and it was co-loaded with the prodrug prednisolone phosphate (PLP) and the structurally similar MRI agent Gd-DTPAMA-CHOL. Importantly, the in vitro release of PLP and Gd-DTPAMA-CHOL from the nanocarrier showed similar profiles, validating the potential impact of the MRI agent as an imaging reporter for the drug release. On the other hand, the nanobubbles were also detectable by US imaging both in vitro and in vivo. Therefore, the temporal evolution of both MRI and US contrast after the administration of the proposed nanosystem could report on the delivery and the release kinetics of the transported drug in a given lesion. Full article

(This article belongs to the Section Biology and Medicines)

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30 pages, 9398 KiB

Open AccessFeature PaperEditor’s ChoiceReview

Exocytosis of Nanoparticles: A Comprehensive Review

by Jie Liu, Yuan-Yuan Liu, Chen-Si Li, Aoneng Cao and Haifang Wang

Nanomaterials 2023, 13(15), 2215; https://doi.org/10.3390/nano13152215 - 30 Jul 2023

Cited by 5 | Viewed by 1673

Abstract

Both biomedical applications and safety assessments of manufactured nanomaterials require a thorough understanding of the interaction between nanomaterials and cells, including how nanomaterials enter cells, transport within cells, and leave cells. However, compared to the extensively studied uptake and trafficking of nanoparticles (NPs) [...] Read more.

Both biomedical applications and safety assessments of manufactured nanomaterials require a thorough understanding of the interaction between nanomaterials and cells, including how nanomaterials enter cells, transport within cells, and leave cells. However, compared to the extensively studied uptake and trafficking of nanoparticles (NPs) in cells, less attention has been paid to the exocytosis of NPs. Yet exocytosis is an indispensable process of regulating the content of NPs in cells, which in turn influences, even decides, the toxicity of NPs to cells. A comprehensive understanding of the mechanisms and influencing factors of the exocytosis of NPs is not only essential for the safety assessment of NPs but also helpful for guiding the design of safe and highly effective NP-based materials for various purposes. Herein, we review the current status and progress of studies on the exocytosis of NPs. Firstly, we introduce experimental procedures and considerations. Then, exocytosis mechanisms/pathways are summarized with a detailed introduction of the main pathways (lysosomal and endoplasmic reticulum/Golgi pathway) and the role of microtubules; the patterns of exocytosis kinetics are presented and discussed. Subsequently, the influencing factors (initial content and location of intracellular NPs, physiochemical properties of NPs, cell type, and extracellular conditions) are fully discussed. Although there are inconsistent results, some rules are obtained, like smaller and charged NPs are more easily excreted. Finally, the challenges and future directions in the field have been discussed. Full article

(This article belongs to the Special Issue Safe Design and Toxicology In Vitro of Nanomaterials)

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12 pages, 2756 KiB

Open AccessEditor’s ChoiceArticle

Atomic-Layer Engineering of La_2−xSr_xCuO₄—La_2−xSr_xZnO₄ Heterostructures

by Xiaotao Xu, Xi He, Anthony T. Bollinger, Xiaoyan Shi and Ivan Božović

Nanomaterials 2023, 13(15), 2207; https://doi.org/10.3390/nano13152207 - 29 Jul 2023

Viewed by 823

Abstract

The fabrication of trilayer superconductor-insulator-superconductor (SIS) Josephson junctions with high-temperature superconductor (HTS) electrodes requires atomically perfect interfaces. Therefore, despite great interest and efforts, this remained a challenge for over three decades. Here, we report the discovery of a new family of metastable materials, [...] Read more.

The fabrication of trilayer superconductor-insulator-superconductor (SIS) Josephson junctions with high-temperature superconductor (HTS) electrodes requires atomically perfect interfaces. Therefore, despite great interest and efforts, this remained a challenge for over three decades. Here, we report the discovery of a new family of metastable materials, La_2−xSr_xZnO₄ (LSZO), synthesized by atomic-layer-by-layer molecular beam epitaxy (ALL-MBE). We show that LSZO is insulating and epitaxially compatible with an HTS compound, La_2−xSr_xCuO₄ (LSCO). Since the “parent” compound La₂ZnO₄ (LZO) is easier to grow, here we focus on this material as our insulating layer. Growing LZO at very low temperatures to reduce cation interdiffusion makes LSCO/LZO interfaces atomically sharp. We show that in LSCO/LZO/LSCO trilayers, the superconducting properties of the LSCO electrodes remain undiminished, unlike in previous attempts with insulator barriers made of other materials. This opens prospects to produce high-quality HTS tunnel junctions. Full article

(This article belongs to the Special Issue Recent Advances in Nanowires and Superconductors)

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15 pages, 2982 KiB

Open AccessEditor’s ChoiceArticle

Unraveling the Mechanisms of Ch-SeNP Cytotoxicity against Cancer Cells: Insights from Targeted and Untargeted Metabolomics

by Hector Estevez, Estefania Garcia-Calvo, Maria L. Mena, Roberto Alvarez-Fernandez Garcia and Jose L. Luque-Garcia

Nanomaterials 2023, 13(15), 2204; https://doi.org/10.3390/nano13152204 - 29 Jul 2023

Cited by 2 | Viewed by 1142

Abstract

Although chitosan-stabilized selenium nanoparticles (Ch-SeNPs) have emerged as a promising chemical form of selenium for anticancer purposes, gathering more profound knowledge related to molecular dysfunctions contributes significantly to the promotion of their evolution as a chemotherapeutic drug. In this sense, metabolites are the [...] Read more.

Although chitosan-stabilized selenium nanoparticles (Ch-SeNPs) have emerged as a promising chemical form of selenium for anticancer purposes, gathering more profound knowledge related to molecular dysfunctions contributes significantly to the promotion of their evolution as a chemotherapeutic drug. In this sense, metabolites are the end products in the flow of gene expression and, thus, the most sensitive to changes in the physiological state of a biological system. Therefore, metabolomics provides a functional readout of the biochemical activity and cell state. In the present study, we evaluated alterations in the metabolomes of HepG2 cells after the exposure to Ch-SeNPs to elucidate the biomolecular mechanisms involved in their therapeutic effect. A targeted metabolomic approach was conducted to evaluate the levels of four of the main energy-related metabolites (adenosine triphosphate (ATP); adenosine diphosphate (ADP); nicotinamide adenine dinucleotide (NAD⁺); and 1,4-dihydronicotinamide adenine dinucleotide (NADH)), revealing alterations as a result of exposure to Ch-SeNPs related to a shortage in the energy supply system in the cell. In addition, an untargeted metabolomic experiment was performed, which allowed for the study of alterations in the global metabolic profile as a consequence of Ch-SeNP exposure. The results indicate that the TCA cycle and glycolytic pathways were impaired, while alternative pathways such as glutaminolysis and cysteine metabolism were upregulated. Additionally, increased fructose levels suggested the induction of hypoxia-like conditions. These findings highlight the potential of Ch-SeNPs to disrupt cancer cell metabolism and provide insights into the mechanisms underlying their antitumor effects. Full article

(This article belongs to the Special Issue Biomedical Applications of Metallic Nanoparticles)

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12 pages, 2283 KiB

Open AccessEditor’s ChoiceArticle

Overcoming the Fermi-Level Pinning Effect in the Nanoscale Metal and Silicon Interface

by Zih-Chun Su and Ching-Fuh Lin

Nanomaterials 2023, 13(15), 2193; https://doi.org/10.3390/nano13152193 - 28 Jul 2023

Viewed by 2062

Abstract

Silicon-based photodetectors are attractive as low-cost and environmentally friendly optical sensors. Also, their compatibility with complementary metal-oxide-semiconductor (CMOS) technology is advantageous for the development of silicon photonics systems. However, extending optical responsivity of silicon-based photodetectors to the mid-infrared (mid-IR) wavelength range remains challenging. [...] Read more.

Silicon-based photodetectors are attractive as low-cost and environmentally friendly optical sensors. Also, their compatibility with complementary metal-oxide-semiconductor (CMOS) technology is advantageous for the development of silicon photonics systems. However, extending optical responsivity of silicon-based photodetectors to the mid-infrared (mid-IR) wavelength range remains challenging. In developing mid-IR infrared Schottky detectors, nanoscale metals are critical. Nonetheless, one key factor is the Fermi-level pinning effect at the metal/silicon interface and the presence of metal-induced gap states (MIGS). Here, we demonstrate the utilization of the passivated surface layer on semiconductor materials as an insulating material in metal-insulator-semiconductor (MIS) contacts to mitigate the Fermi-level pinning effect. The removal of Fermi-level pinning effectively reduces the Schottky barrier height by 12.5% to 16%. The demonstrated devices exhibit a high responsivity of up to 234 μA/W at a wavelength of 2 μm, 48.2 μA/W at 3 μm, and 1.75 μA/W at 6 μm. The corresponding detectivities at 2 and 3 μm are 1.17 × 10⁸ cm Hz^1/2 W⁻¹ and 2.41 × 10⁷ cm Hz^1/2 W⁻¹, respectively. The expanded sensing wavelength range contributes to the application development of future silicon photonics integration platforms. Full article

(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)

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32 pages, 8297 KiB

Open AccessEditor’s ChoiceReview

A Breakthrough in Photocatalytic Wastewater Treatment: The Incredible Potential of g-C₃N₄/Titanate Perovskite-Based Nanocomposites

by Rashmiranjan Patra, Pranjyan Dash, Pradeep Kumar Panda and Po-Chih Yang

Nanomaterials 2023, 13(15), 2173; https://doi.org/10.3390/nano13152173 - 26 Jul 2023

Cited by 5 | Viewed by 1906

Abstract

Water pollution has emerged as a major global environmental crisis due to the massive contamination of water resources by the textile dyeing industry, organic waste, and agricultural residue. Since water is fundamental to life, this grave disregard puts lives at risk, making the [...] Read more.

Water pollution has emerged as a major global environmental crisis due to the massive contamination of water resources by the textile dyeing industry, organic waste, and agricultural residue. Since water is fundamental to life, this grave disregard puts lives at risk, making the protection of water resources a serious issue today. Recent research has shown great interest in improving the photocatalytic performance of graphitic carbon nitride (g-C₃N₄) for wastewater treatment. However, the photocatalytic removal activity of pure g-C₃N₄ is poor, owing to its minimal surface area, fast recombination of photo-generated electron–hole pairs, and poor light absorption. Recently, titanate perovskites (TNPs) have attracted significant attention in both environmental remediation and energy conversion due to their exceptional structural, optical, physiochemical, electrical, and thermal properties. Accordingly, TNPs can initiate a variety of surface catalytic reactions and are regarded as an emerging category of photocatalysts for sustainability and energy-related industries when exposed to illumination. Therefore, in this review article, we critically discuss the recent developments of extensively developed g-C₃N₄/TNPs that demonstrate photocatalytic applications for wastewater treatment. The different synthetic approaches and the chemical composition of g-C₃N₄/TNP composites are presented. Additionally, this review highlights the global research trends related to these materials. Furthermore, this review provides insight into the various photocatalytic mechanisms, including their potential impact and significance. Also, the challenges faced by such materials and their future scope are discussed. Full article

(This article belongs to the Special Issue Nanostructured and Functional Nanomaterials for Energy Storage and Removal of Pollutants)

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16 pages, 75254 KiB

Open AccessEditor’s ChoiceArticle

Electric Field-Induced Nano-Assembly Formation: First Evidence of Silicon Superclusters with a Giant Permanent Dipole Moment

by Fatme Jardali, Jacqueline Tran, Frédéric Liège, Ileana Florea, Mohamed E. Leulmi and Holger Vach

Nanomaterials 2023, 13(15), 2169; https://doi.org/10.3390/nano13152169 - 26 Jul 2023

Cited by 1 | Viewed by 976

Abstract

The outstanding properties of silicon nanoparticles have been extensively investigated during the last few decades. Experimental evidence and applications of their theoretically predicted permanent electric dipole moment, however, have only been reported for silicon nanoclusters (SiNCs) for a size of about one to [...] Read more.

The outstanding properties of silicon nanoparticles have been extensively investigated during the last few decades. Experimental evidence and applications of their theoretically predicted permanent electric dipole moment, however, have only been reported for silicon nanoclusters (SiNCs) for a size of about one to two nanometers. Here, we have explored the question of whether suitable plasma conditions could lead to much larger silicon clusters with significantly stronger permanent electric dipole moments. A pulsed plasma approach was used for SiNC production and surface deposition. The absorption spectra of the deposited SiNCs were recorded using enhanced darkfield hyperspectral microscopy and compared to time-dependent DFT calculations. Atomic force microscopy and transmission electron microscopy observations completed our study, showing that one-to-two-nanometer SiNCs can, indeed, be used to assemble much larger ”superclusters” with a size of tens of nanometers. These superclusters possess extremely high permanent electric dipole moments that can be exploited to orient and guide these clusters with external electric fields, opening the path to the controlled architecture of silicon nanostructures. Full article

(This article belongs to the Special Issue Self-Assembly of Atomically Precise Nanoclusters: From Irregular Assembly to Crystalline Assembly)

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19 pages, 9316 KiB

Open AccessEditor’s ChoiceArticle

In Situ Ultra-Small- and Small-Angle X-ray Scattering Study of ZnO Nanoparticle Formation and Growth through Chemical Bath Deposition in the Presence of Polyvinylpyrrolidone

by Karina Abitaev, Petia Atanasova, Joachim Bill, Natalie Preisig, Ivan Kuzmenko, Jan Ilavsky, Yun Liu and Thomas Sottmann

Nanomaterials 2023, 13(15), 2180; https://doi.org/10.3390/nano13152180 - 26 Jul 2023

Viewed by 1212

Abstract

ZnO inverse opals combine the outstanding properties of the semiconductor ZnO with the high surface area of the open-porous framework, making them valuable photonic and catalysis support materials. One route to produce inverse opals is to mineralize the voids of close-packed polymer nanoparticle [...] Read more.

ZnO inverse opals combine the outstanding properties of the semiconductor ZnO with the high surface area of the open-porous framework, making them valuable photonic and catalysis support materials. One route to produce inverse opals is to mineralize the voids of close-packed polymer nanoparticle templates by chemical bath deposition (CBD) using a ZnO precursor solution, followed by template removal. To ensure synthesis control, the formation and growth of ZnO nanoparticles in a precursor solution containing the organic additive polyvinylpyrrolidone (PVP) was investigated by in situ ultra-small- and small-angle X-ray scattering (USAXS/SAXS). Before that, we studied the precursor solution by in-house SAXS at T = 25 °C, revealing the presence of a PVP network with semiflexible chain behavior. Heating the precursor solution to 58 °C or 63 °C initiates the formation of small ZnO nanoparticles that cluster together, as shown by complementary transmission electron microscopy images (TEM) taken after synthesis. The underlying kinetics of this process could be deciphered by quantitatively analyzing the USAXS/SAXS data considering the scattering contributions of particles, clusters, and the PVP network. A nearly quantitative description of both the nucleation and growth period could be achieved using the two-step Finke–Watzky model with slow, continuous nucleation followed by autocatalytic growth. Full article

(This article belongs to the Special Issue Nanomaterials for Chemical Engineering (Volume II))

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10 pages, 3407 KiB

Open AccessEditor’s ChoiceArticle

The Atomic Observation of the Structural Change Process in Pt Networks in Air Using Environmental Cell Scanning Transmission Electron Microscopy

by Masaki Takeguchi, Toshiaki Takei and Kazutaka Mitsuishi

Nanomaterials 2023, 13(15), 2170; https://doi.org/10.3390/nano13152170 - 26 Jul 2023

Cited by 1 | Viewed by 818

Abstract

The structural change in Pt networks composed of multiple chain connections among grains was observed in air at 1 atm using atomic-resolution environmental cell scanning transmission electron microscopy. An aberration-corrected incident electron probe with a wide convergence angle made it possible to increase [...] Read more.

The structural change in Pt networks composed of multiple chain connections among grains was observed in air at 1 atm using atomic-resolution environmental cell scanning transmission electron microscopy. An aberration-corrected incident electron probe with a wide convergence angle made it possible to increase the depth resolution that contributes to enhancing the signal-to-noise ratio of Pt network samples in air in an environmental cell, resulting in the achievement of atomic-resolution imaging. The exposure of the Pt networks to gas molecules under Brownian motion, stimulated by electron beams in the air, increases the collision probability between gas molecules and Pt networks, and the Pt networks are more intensely stressed from all directions than in a situation without electron irradiation. By increasing the electron beam dose rate, the structural change of the Pt networks became significant. Dynamic observation on an atomic scale suggested that the structural change of the networks was not attributed to the surface atomic-diffusion-induced step motion but mainly caused by the movement and deformation of unstable grains and grain boundaries. The oxidized surface layers may be one of the factors hindering the surface atomic step motion, mitigating the change in the size of the grains and grain boundaries. Full article

(This article belongs to the Special Issue Transmission Electron Microscopy for Nanomaterials Research Advances)

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12 pages, 5793 KiB

Open AccessEditor’s ChoiceArticle

Preparation of Ce-MnO_x Composite Oxides via Coprecipitation and Their Catalytic Performance for CO Oxidation

by Junsheng Yang, Jie Li, Jiangang Kang, Wenkang Liu, Yijian Kuang, Hua Tan, Zhensen Yu, Liu Yang, Xuejin Yang, Kui Yu and Yiquan Fan

Nanomaterials 2023, 13(15), 2158; https://doi.org/10.3390/nano13152158 - 25 Jul 2023

Cited by 1 | Viewed by 1046

Abstract

Ce-MnO_x composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60–140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation [...] Read more.

Ce-MnO_x composite oxide catalysts with different proportions were prepared using the coprecipitation method, and the CO-removal ability of the catalysts with the tested temperature range of 60–140 °C was investigated systematically. The effect of Ce and Mn ratios on the catalytic oxidation performance of CO was investigated using X-ray diffraction (XRD), X-ray energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), H₂ temperature programmed reduction (H₂-TPR), CO-temperature programmed desorption (CO-TPD), and in situ infrared spectra. The experimental results reveal that under the same test conditions, the CO conversion rate of pure Mn₃O₄ reaches 95.4% at 170 °C. Additionally, at 140 °C, the Ce-MnO_x series composite oxide catalyst converts CO at a rate of over 96%, outperforming single-phase Mn₃O₄ in terms of catalytic performance. With the decrement in Ce content, the performance of Ce-MnO_x series composite oxide catalysts first increase and then decrease. The Ce MnO_x catalyst behaves best when Ce:Mn = 1:1, with a CO conversion rate of 99.96% at 140 °C and 91.98% at 100 °C. Full article

(This article belongs to the Special Issue Nanocatalysts for Air Purification)

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37 pages, 4294 KiB

Open AccessEditor’s ChoiceReview

Contrasting Properties of Polymeric Nanocarriers for MRI-Guided Drug Delivery

by Natalia Łopuszyńska and Władysław P. Węglarz

Nanomaterials 2023, 13(15), 2163; https://doi.org/10.3390/nano13152163 - 25 Jul 2023

Cited by 1 | Viewed by 1378

Abstract

Poor pharmacokinetics and low aqueous solubility combined with rapid clearance from the circulation of drugs result in their limited effectiveness and generally high therapeutic doses. The use of nanocarriers for drug delivery can prevent the rapid degradation of the drug, leading to its [...] Read more.

Poor pharmacokinetics and low aqueous solubility combined with rapid clearance from the circulation of drugs result in their limited effectiveness and generally high therapeutic doses. The use of nanocarriers for drug delivery can prevent the rapid degradation of the drug, leading to its increased half-life. It can also improve the solubility and stability of drugs, advance their distribution and targeting, ensure a sustained release, and reduce drug resistance by delivering multiple therapeutic agents simultaneously. Furthermore, nanotechnology enables the combination of therapeutics with biomedical imaging agents and other treatment modalities to overcome the challenges of disease diagnosis and therapy. Such an approach is referred to as “theranostics” and aims to offer a more patient-specific approach through the observation of the distribution of contrast agents that are linked to therapeutics. The purpose of this paper is to present the recent scientific reports on polymeric nanocarriers for MRI-guided drug delivery. Polymeric nanocarriers are a very broad and versatile group of materials for drug delivery, providing high loading capacities, improved pharmacokinetics, and biocompatibility. The main focus was on the contrasting properties of proposed polymeric nanocarriers, which can be categorized into three main groups: polymeric nanocarriers (1) with relaxation-type contrast agents, (2) with chemical exchange saturation transfer (CEST) properties, and (3) with direct detection contrast agents based on fluorinated compounds. The importance of this aspect tends to be downplayed, despite its being essential for the successful design of applicable theranostic nanocarriers for image-guided drug delivery. If available, cytotoxicity and therapeutic effects were also summarized. Full article

(This article belongs to the Special Issue Nanomaterials for Magnetic Resonance Imaging)

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23 pages, 9294 KiB

Open AccessEditor’s ChoiceArticle

Phase-Selective Epitaxy of Trigonal and Orthorhombic Bismuth Thin Films on Si (111)

by Abdur Rehman Jalil, Xiao Hou, Peter Schüffelgen, Jin Hee Bae, Elmar Neumann, Gregor Mussler, Lukasz Plucinski and Detlev Grützmacher

Nanomaterials 2023, 13(14), 2143; https://doi.org/10.3390/nano13142143 - 24 Jul 2023

Viewed by 1373

Abstract

Over the past three decades, the growth of Bi thin films has been extensively explored due to their potential applications in various fields such as thermoelectrics, ferroelectrics, and recently for topological and neuromorphic applications, too. Despite significant research efforts in these areas, achieving [...] Read more.

Over the past three decades, the growth of Bi thin films has been extensively explored due to their potential applications in various fields such as thermoelectrics, ferroelectrics, and recently for topological and neuromorphic applications, too. Despite significant research efforts in these areas, achieving reliable and controllable growth of high-quality Bi thin-film allotropes has remained a challenge. Previous studies have reported the growth of trigonal and orthorhombic phases on various substrates yielding low-quality epilayers characterized by surface morphology. In this study, we present a systematic growth investigation, enabling the high-quality growth of Bi epilayers on Bi-terminated Si (111) 1 × 1 surfaces using molecular beam epitaxy. Our work yields a phase map that demonstrates the realization of trigonal, orthorhombic, and pseudocubic thin-film allotropes of Bi. In-depth characterization through X-ray diffraction (XRD) techniques and scanning transmission electron microscopy (STEM) analysis provides a comprehensive understanding of phase segregation, phase stability, phase transformation, and phase-dependent thickness limitations in various Bi thin-film allotropes. Our study provides recipes for the realization of high-quality Bi thin films with desired phases, offering opportunities for the scalable refinement of Bi into quantum and neuromorphic devices and for revisiting technological proposals for this versatile material platform from the past 30 years. Full article

(This article belongs to the Special Issue Topological Materials in Low Dimensions)

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14 pages, 2350 KiB

Open AccessEditor’s ChoiceArticle

Acute Aquatic Toxicity to Zebrafish and Bioaccumulation in Marine Mussels of Antimony Tin Oxide Nanoparticles

by Ivone Pinheiro, Monica Quarato, Antonio Moreda-Piñeiro, Ana Vieira, Virginie Serin, David Neumeyer, Nicolas Ratel-Ramond, Sébastien Joulié, Alain Claverie, Miguel Spuch-Calvar, Miguel A. Correa-Duarte, Alexandre Campos, José Carlos Martins, Pilar Bermejo-Barrera, Marisa P. Sarriá, Laura Rodriguez-Lorenzo and Begoña Espiña

Nanomaterials 2023, 13(14), 2112; https://doi.org/10.3390/nano13142112 - 20 Jul 2023

Viewed by 1098

Abstract

Antimony tin oxide (Sb₂O₅/SnO₂) is effective in the absorption of infrared radiation for applications, such as skylights. As a nanoparticle (NP), it can be incorporated into films or sheets providing infrared radiation attenuation while allowing for a [...] Read more.

Antimony tin oxide (Sb₂O₅/SnO₂) is effective in the absorption of infrared radiation for applications, such as skylights. As a nanoparticle (NP), it can be incorporated into films or sheets providing infrared radiation attenuation while allowing for a transparent final product. The acute toxicity exerted by commercial Sb₂O₅/SnO₂ (ATO) NPs was studied in adults and embryos of zebrafish (Danio rerio). Our results suggest that these NPs do not induce an acute toxicity in zebrafish, either adults or embryos. However, some sub-lethal parameters were altered: heart rate and spontaneous movements. Finally, the possible bioaccumulation of these NPs in the aquacultured marine mussel Mytilus sp. was studied. A quantitative analysis was performed using single particle inductively coupled plasma mass spectrometry (sp-ICP-MS). The results indicated that, despite being scarce (2.31 × 10⁶ ± 9.05 × 10⁵ NPs/g), there is some accumulation of the ATO NPs in the mussel. In conclusion, commercial ATO NPs seem to be quite innocuous to aquatic organisms; however, the fact that some of the developmental parameters in zebrafish embryos are altered should be considered for further investigation. More in-depth analysis of these NPs transformations in the digestive tract of humans is needed to assess whether their accumulation in mussels presents an actual risk to humans. Full article

(This article belongs to the Special Issue Ecotoxicology and Risk Assessment of Engineered Nanomaterials)

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14 pages, 15522 KiB

Open AccessEditor’s ChoiceArticle

Influence of Solvents and Adsorption of Organic Molecules on the Properties of CVD Synthesized 2D MoS₂

by Antun Lovro Brkić, Antonio Supina, Davor Čapeta, Lucija Dončević, Lucija Ptiček, Šimun Mandić, Livio Racané and Ida Delač

Nanomaterials 2023, 13(14), 2115; https://doi.org/10.3390/nano13142115 - 20 Jul 2023

Viewed by 1032

Abstract

We present a simple method for modification of 2D materials by drop-casting of the organic molecule in solution on the 2D material under ambient conditions. Specifically, we investigated the adsorption of 6-(4,5-Dihydro-1H-imidazol-3-ium-2-yl)-2-(naphthalene-2-yl)benzothiazole methanesulfonate (L63MS) organic molecule on 2D MoS

_{2}

. [...] Read more.

We present a simple method for modification of 2D materials by drop-casting of the organic molecule in solution on the 2D material under ambient conditions. Specifically, we investigated the adsorption of 6-(4,5-Dihydro-1H-imidazol-3-ium-2-yl)-2-(naphthalene-2-yl)benzothiazole methanesulfonate (L63MS) organic molecule on 2D MoS

_{2}

. To better understand the effect of the organic molecule on the 2D material, we also investigated the impact of solvents alone on the materials’ properties. The MoS

_{2}

samples were synthesized using ambient pressure chemical vapor deposition. Atomic force microscopy, Raman spectroscopy, photoluminescence spectroscopy and optical microscopy were used to characterize the samples. The measurements were performed after synthesis, after the drop-casting of solvents and after the drop-casting of organic molecule solutions. Our results indicate that the used organic molecule effectively adsorbs on and prompts discernible changes in the (opto)electronic properties of the 2D material. These changes encompass variations in the Raman spectra shape, alterations in the photoluminescence (PL) signal characteristics and modifications in excitonic properties. Such alterations can be linked to various phenomena including doping, bandgap modifications, introduction or healing of defects and that the solvent plays a crucial role in the process. Our study provides insights into the modification of 2D materials under ambient conditions and highlights the importance of solvent selection in the process. Full article

(This article belongs to the Special Issue 2D Materials and van der Waals Heterostructures for Optoelectronic Devices)

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13 pages, 4704 KiB

Open AccessEditor’s ChoiceArticle

Sub-THz Vibrational Dynamics in Ordered Mesoporous Silica Nanoparticles

by Eduardo Hernando Abad, Frédéric Bouyer, Laroussi Chaabane, Alan Zerrouki, Jérémie Margueritat and Lucien Saviot

Nanomaterials 2023, 13(14), 2078; https://doi.org/10.3390/nano13142078 - 15 Jul 2023

Cited by 1 | Viewed by 1031

Abstract

The vibrational dynamics in the sub-THz range of mesoporous silica nanoparticles (MSNs) having ordered cylindrical mesopores was investigated. MCM-41 and SBA-15 particles were synthesized, and their structure was determined using scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD), N₂ physisorption analyses, and [...] Read more.

The vibrational dynamics in the sub-THz range of mesoporous silica nanoparticles (MSNs) having ordered cylindrical mesopores was investigated. MCM-41 and SBA-15 particles were synthesized, and their structure was determined using scanning electron microscopy (SEM), low-angle X-ray diffraction (XRD), N₂ physisorption analyses, and Raman scattering. Brillouin scattering measurements are reported and enabled determining the stiffness of the silica walls (speed of sound) using finite element calculations for the ordered mesoporous structure. The relevance of this approach is discussed based on the comparison between the numerical and experimental results and previous works reported in the literature. Full article

(This article belongs to the Section Synthesis, Interfaces and Nanostructures)

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12 pages, 6422 KiB

Open AccessEditor’s ChoiceArticle

Synthesis of Multiple Emission Carbon Dots from Dihydroxybenzoic Acid via Decarboxylation Process

by Pengfei Li, Jijian Xu, Ziye Shen, Wenning Liu, Li An, Dan Qu, Xiayan Wang and Zaicheng Sun

Nanomaterials 2023, 13(14), 2062; https://doi.org/10.3390/nano13142062 - 13 Jul 2023

Cited by 1 | Viewed by 1194

Abstract

Carbon dots (CDs), as a new zero-dimensional carbon-based nanomaterial with desirable optical properties, exhibit great potential for many application fields. However, the preparation technique of multiple emission CDs with high yield is difficult and complex. Therefore, exploring the large-scale and straightforward synthesis of [...] Read more.

Carbon dots (CDs), as a new zero-dimensional carbon-based nanomaterial with desirable optical properties, exhibit great potential for many application fields. However, the preparation technique of multiple emission CDs with high yield is difficult and complex. Therefore, exploring the large-scale and straightforward synthesis of multicolor CDs from a simple carbon source is necessary. In this work, the solvent-free method prepares a series of multicolor emission CDs from dihydroxybenzoic acid (DHBA). The maximum emission wavelengths are 408, 445, 553, 580, and 610 nm, respectively, covering the visible light region. The 2,4- and 2,6-CDs possess the longer emission wavelength caused by the 2,4-, and 2,6-DHBA easily undergo decarboxylation to form the larger sp² domain graphitized structure. These CDs incorporated with g-C₃N₄ can significantly improve the photocatalytic water-splitting hydrogen production rate by extending the visible light absorption and enhancing the charge separation efficiency. The long-wavelength emission CDs can further enhance photocatalytic activity primarily by improving visible light absorption efficiency. Full article

(This article belongs to the Special Issue Nano-Composites for Photo- and Electrocatalysis and Its Application)

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17 pages, 5222 KiB

Open AccessEditor’s ChoiceArticle

Incorporation/Enrichment of 3D Bioprinted Constructs by Biomimetic Nanoparticles: Tuning Printability and Cell Behavior in Bone Models

by Tiziana Fischetti, Giorgia Borciani, Sofia Avnet, Katia Rubini, Nicola Baldini, Gabriela Graziani and Elisa Boanini

Nanomaterials 2023, 13(14), 2040; https://doi.org/10.3390/nano13142040 - 10 Jul 2023

Cited by 1 | Viewed by 1089

Abstract

Reproducing in vitro a model of the bone microenvironment is a current need. Preclinical in vitro screening, drug discovery, as well as pathophysiology studies may benefit from in vitro three-dimensional (3D) bone models, which permit high-throughput screening, low costs, and high reproducibility, overcoming [...] Read more.

Reproducing in vitro a model of the bone microenvironment is a current need. Preclinical in vitro screening, drug discovery, as well as pathophysiology studies may benefit from in vitro three-dimensional (3D) bone models, which permit high-throughput screening, low costs, and high reproducibility, overcoming the limitations of the conventional two-dimensional cell cultures. In order to obtain these models, 3D bioprinting offers new perspectives by allowing a combination of advanced techniques and inks. In this context, we propose the use of hydroxyapatite nanoparticles, assimilated to the mineral component of bone, as a route to tune the printability and the characteristics of the scaffold and to guide cell behavior. To this aim, both stoichiometric and Sr-substituted hydroxyapatite nanocrystals are used, so as to obtain different particle shapes and solubility. Our findings show that the nanoparticles have the desired shape and composition and that they can be embedded in the inks without loss of cell viability. Both Sr-containing and stoichiometric hydroxyapatite crystals permit enhancing the printing fidelity of the scaffolds in a particle-dependent fashion and control the swelling behavior and ion release of the scaffolds. Once Saos-2 cells are encapsulated in the scaffolds, high cell viability is detected until late time points, with a good cellular distribution throughout the material. We also show that even minor modifications in the hydroxyapatite particle characteristics result in a significantly different behavior of the scaffolds. This indicates that the use of calcium phosphate nanocrystals and structural ion-substitution is a promising approach to tune the behavior of 3D bioprinted constructs. Full article

(This article belongs to the Special Issue Applications of Calcium Phosphates-Based Nanostructured Materials and Coatings)

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42 pages, 7755 KiB

Open AccessEditor’s ChoiceReview

Recent Progress in Multifunctional Graphene-Based Nanocomposites for Photocatalysis and Electrocatalysis Application

by Zanhe Yang, Siqi Zhou, Xiangyu Feng, Nannan Wang, Oluwafunmilola Ola and Yanqiu Zhu

Nanomaterials 2023, 13(13), 2028; https://doi.org/10.3390/nano13132028 - 7 Jul 2023

Cited by 4 | Viewed by 1983

Abstract

The global energy shortage and environmental degradation are two major issues of concern in today’s society. The production of renewable energy and the treatment of pollutants are currently the mainstream research directions in the field of photocatalysis. In addition, over the last decade [...] Read more.

The global energy shortage and environmental degradation are two major issues of concern in today’s society. The production of renewable energy and the treatment of pollutants are currently the mainstream research directions in the field of photocatalysis. In addition, over the last decade or so, graphene (GR) has been widely used in photocatalysis due to its unique physical and chemical properties, such as its large light-absorption range, high adsorption capacity, large specific surface area, and excellent electronic conductivity. Here, we first introduce the unique properties of graphene, such as its high specific surface area, chemical stability, etc. Then, the basic principles of photocatalytic hydrolysis, pollutant degradation, and the photocatalytic reduction of CO₂ are summarized. We then give an overview of the optimization strategies for graphene-based photocatalysis and the latest advances in its application. Finally, we present challenges and perspectives for graphene-based applications in this field in light of recent developments. Full article

(This article belongs to the Special Issue Advances in Nano-Electrochemical Materials and Devices)

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15 pages, 8835 KiB

Open AccessEditor’s ChoiceArticle

Nanosurface Texturing for Enhancing the Antibacterial Effect of Biodegradable Metal Zinc: Surface Modifications

by Enmao Xiang, Corey S. Moran, Sašo Ivanovski and Abdalla Abdal-hay

Nanomaterials 2023, 13(13), 2022; https://doi.org/10.3390/nano13132022 - 7 Jul 2023

Cited by 4 | Viewed by 1279

Abstract

Zinc (Zn) as a biodegradable metal has attracted research interest for bone reconstruction, with the aim of eliminating the need for a second removal surgery and minimizing the implant-to-bone transfer of stress-shielding to maintain bone regeneration. In addition, Zn has been shown to [...] Read more.

Zinc (Zn) as a biodegradable metal has attracted research interest for bone reconstruction, with the aim of eliminating the need for a second removal surgery and minimizing the implant-to-bone transfer of stress-shielding to maintain bone regeneration. In addition, Zn has been shown to have antibacterial properties, particularly against Gram-negative bacteria, and is often used as a surface coating to inhibit bacterial growth and biofilm formation. However, the antibacterial property of Zn is still suboptimal in part due to low Zn ion release during degradation that has to be further improved in order to meet clinical requirements. This work aims to perform an innovative one-step surface modification using a nitric acid treatment to accelerate Zn ion release by increasing surface roughness, thereby endowing an effective antimicrobial property and biofilm formation inhibition. The antibacterial performance against Staphylococci aureus was evaluated by assessing biofilm formation and adhesion using quantitative assays. The surface roughness of acid-treated Zn (Ra ~ 30 nm) was significantly higher than polished Zn (Ra ~ 3 nm) and corresponded with the marked inhibition of bacterial biofilm, and this is likely due to the increased surface contact area and Zn ion accumulation. Overall, surface modification due to nitric acid etching appears to be an effective technique that can produce unique morphological surface structures and enhance the antibacterial properties of biodegradable Zn-based materials, thus increasing the translation potential toward multiple biomedical applications. Full article

(This article belongs to the Special Issue Nanostructured Biomaterials for Tissue Repair and Anti-infection)

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12 pages, 403 KiB

Open AccessEditor’s ChoiceReview

Slater–Pauling Behavior in Half-Metallic Heusler Compounds

by Iosif Galanakis

Nanomaterials 2023, 13(13), 2010; https://doi.org/10.3390/nano13132010 - 5 Jul 2023

Cited by 8 | Viewed by 1561

Abstract

Heusler materials have become very popular over the last two decades due to the half-metallic properties of a large number of Heusler compounds. The latter are magnets that present a metallic behavior for the spin-up and a semiconducting behavior for the spin-down electronic [...] Read more.

Heusler materials have become very popular over the last two decades due to the half-metallic properties of a large number of Heusler compounds. The latter are magnets that present a metallic behavior for the spin-up and a semiconducting behavior for the spin-down electronic band structure leading to a variety of spintronic applications, and Slater–Pauling rules have played a major role in the development of this research field. These rules have been derived using ab initio electronic structure calculations and directly connecting the electronic properties (existence of spin-down energy gap) to the magnetic properties (total spin magnetic moment). Their exact formulation depends on the half-metallic family under study and can be derived if the hybridization of the orbitals at various sites is taken into account. In this review, the origin and formulation of the Slater–Pauling rules for various families of Heusler compounds, derived during these two last decades, is presented. Full article

(This article belongs to the Special Issue First-Principle Calculation Study of Nanomaterials)

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54 pages, 10594 KiB

Open AccessEditor’s ChoiceReview

Advancing Thermoelectric Materials: A Comprehensive Review Exploring the Significance of One-Dimensional Nano Structuring

by Mustafa Majid Rashak Al-Fartoos, Anurag Roy, Tapas K. Mallick and Asif Ali Tahir

Nanomaterials 2023, 13(13), 2011; https://doi.org/10.3390/nano13132011 - 5 Jul 2023

Cited by 8 | Viewed by 2408

Abstract

Amidst the global challenges posed by pollution, escalating energy expenses, and the imminent threat of global warming, the pursuit of sustainable energy solutions has become increasingly imperative. Thermoelectricity, a promising form of green energy, can harness waste heat and directly convert it into [...] Read more.

Amidst the global challenges posed by pollution, escalating energy expenses, and the imminent threat of global warming, the pursuit of sustainable energy solutions has become increasingly imperative. Thermoelectricity, a promising form of green energy, can harness waste heat and directly convert it into electricity. This technology has captivated attention for centuries due to its environmentally friendly characteristics, mechanical stability, versatility in size and substrate, and absence of moving components. Its applications span diverse domains, encompassing heat recovery, cooling, sensing, and operating at low and high temperatures. However, developing thermoelectric materials with high-performance efficiency faces obstacles such as high cost, toxicity, and reliance on rare-earth elements. To address these challenges, this comprehensive review encompasses pivotal aspects of thermoelectricity, including its historical context, fundamental operating principles, cutting-edge materials, and innovative strategies. In particular, the potential of one-dimensional nanostructuring is explored as a promising avenue for advancing thermoelectric technology. The concept of one-dimensional nanostructuring is extensively examined, encompassing various configurations and their impact on the thermoelectric properties of materials. The profound influence of one-dimensional nanostructuring on thermoelectric parameters is also thoroughly discussed. The review also provides a comprehensive overview of large-scale synthesis methods for one-dimensional thermoelectric materials, delving into the measurement of thermoelectric properties specific to such materials. Finally, the review concludes by outlining prospects and identifying potential directions for further advancements in the field. Full article

(This article belongs to the Special Issue Nanomaterials and Nanofabrication for Solar Cells and Energy Harvesting)

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40 pages, 9793 KiB

Open AccessEditor’s ChoiceReview

Direct Optical Patterning of Quantum Dots: One Strategy, Different Chemical Processes

by Francesco Antolini

Nanomaterials 2023, 13(13), 2008; https://doi.org/10.3390/nano13132008 - 5 Jul 2023

Viewed by 1575

Abstract

Patterning, stability, and dispersion of the semiconductor quantum dots (scQDs) are three issues strictly interconnected for successful device manufacturing. Recently, several authors adopted direct optical patterning (DOP) as a step forward in photolithography to position the scQDs in a selected area. However, the [...] Read more.

Patterning, stability, and dispersion of the semiconductor quantum dots (scQDs) are three issues strictly interconnected for successful device manufacturing. Recently, several authors adopted direct optical patterning (DOP) as a step forward in photolithography to position the scQDs in a selected area. However, the chemistry behind the stability, dispersion, and patterning has to be carefully integrated to obtain a functional commercial device. This review describes different chemical strategies suitable to stabilize the scQDs both at a single level and as an ensemble. Special attention is paid to those strategies compatible with direct optical patterning (DOP). With the same purpose, the scQDs’ dispersion in a matrix was described in terms of the scQD surface ligands’ interactions with the matrix itself. The chemical processes behind the DOP are illustrated and discussed for five different approaches, all together considering stability, dispersion, and the patterning itself of the scQDs. Full article

(This article belongs to the Special Issue Study on Quantum Dot and Quantum Dot-Based Device)

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