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Nanomaterials, Volume 12, Issue 12 (June-2 2022) – 178 articles

Cover Story (view full-size image): The direct integration of epitaxial III-N heterostructures on Si substrates is a promising platform for optoelectronic device development. Semiconductor light-emitting diodes (LEDs) based on nanowires can be directly fabricated on crystalline-lattice-mismatched Si wafers. We synthesized regular arrays of n-GaN/i-InGaN/p-GaN heterostructured nanowires and tripods on large-area Si/SiO2 substrates prepatterned with the use of cost-effective and rapid microsphere optical lithography. We experimentally show that the n-GaN NWs/n-Si interface demonstrates rectifying behavior and the fabricated n-GaN/i-InGaN/p-GaN NWs-based LEDs have electroluminescence in the broad spectral range, with a maximum near 500 nm, which can be employed for multicolor or white light screen development. View this paper
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15 pages, 3680 KiB  
Article
In Situ Decoration of ZnSnO3 Nanosheets on the Surface of Hollow Zn2SnO4 Octahedrons for Enhanced Solar Energy Application
by Zhengdao Li, Kecheng Liu, Ruixue Sun, Chuanyun Yang and Xiaodi Liu
Nanomaterials 2022, 12(12), 2124; https://doi.org/10.3390/nano12122124 - 20 Jun 2022
Cited by 3 | Viewed by 1795
Abstract
Hierarchical ZnSnO3/Zn2SnO4 porous hollow octahedrons were constructed using the method of combining the acid etching process with the in situ decoration technique for photovoltaic and photocatalytic applications. The composite was used as photoanode of the dye-sensitized solar cells [...] Read more.
Hierarchical ZnSnO3/Zn2SnO4 porous hollow octahedrons were constructed using the method of combining the acid etching process with the in situ decoration technique for photovoltaic and photocatalytic applications. The composite was used as photoanode of the dye-sensitized solar cells (DSSCs), an overall 4.31% photovoltaic conversion efficiency was obtained, nearly a 73.1% improvement over the DSSCs that used Zn2SnO4 solid octahedrons. The composite was also determined to be a high-performance photocatalyst for the removal of heavy metal ion Cr (VI) and antibiotic ciprofloxacin (CIP) in single and co-existing systems under simulated sunlight irradiation. It was remarkable that the composite displayed good reusability and stability in a co-existing system, and the simultaneous removal performance could be restored by a simple acid treatment. These improvements of solar energy utilization were ascribed to the synergetic effect of the hierarchical porous hollow morphology, the introduction of ZnSnO3 nanosheets, and the heterojunction formed between ZnSnO3 and Zn2SnO4, which could improve light harvesting capacity, expedite electron transport and charge-separation efficiencies. Full article
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14 pages, 1882 KiB  
Article
New Insights into Amino-Functionalization of Magnetic Nanoplatelets with Silanes and Phosphonates
by Jelena Papan Djaniš, Griša Grigorij Prinčič, Andraž Mavrič, Alenka Mertelj, Jernej Iskra and Darja Lisjak
Nanomaterials 2022, 12(12), 2123; https://doi.org/10.3390/nano12122123 - 20 Jun 2022
Cited by 1 | Viewed by 1814
Abstract
Magnetic nanoplatelets (NPLs) based on barium hexaferrite (BaFe12O19) are suitable for many applications because of their uniaxial magneto-crystalline anisotropy. Novel materials, such as ferroic liquids, magneto-optic composites, and contrast agents for medical diagnostics, were developed by specific surface functionalization [...] Read more.
Magnetic nanoplatelets (NPLs) based on barium hexaferrite (BaFe12O19) are suitable for many applications because of their uniaxial magneto-crystalline anisotropy. Novel materials, such as ferroic liquids, magneto-optic composites, and contrast agents for medical diagnostics, were developed by specific surface functionalization of the barium hexaferrite NPLs. Our aim was to amino-functionalize the NPLs’ surfaces towards new materials and applications. The amino-functionalization of oxide surfaces is challenging and has not yet been reported for barium hexaferrite NPLs. We selected two amine ligands with two different anchoring groups: an amino-silane and an amino-phosphonate. We studied the effect of the anchoring group, backbone structure, and processing conditions on the formation of the respective surface coatings. The core and coated NPLs were examined with transmission electron microscopy, and their room-temperature magnetic properties were measured. The formation of coatings was followed by electrokinetic measurements, infrared and mass spectroscopies, and thermogravimetric analysis. The most efficient amino-functionalization was enabled by (i) amino-silanization of the NPLs precoated with amorphous silica with (3-aminopropyl)triethoxysilane and (ii) slow addition of amino-phosphonate (i.e., sodium alendronate) to the acidified NPL suspension at 80 °C. Full article
(This article belongs to the Special Issue Magnetic Nanomaterials and Nanostructures)
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14 pages, 7104 KiB  
Article
Evaluation of Ultrasonically ZnO Loading Effect on Photocatalytic Self-Cleaning, UV Protection and Antibacterial Activity of Plasma/Citric Acid-Activated Cotton Fabric
by Muhammad Irfan, Humaira Hussain, Bisma Saleem, Muhammad Saleem, Shazia Shukrullah, Stanislaw Legutko, Jana Petrů, Muhammad Yasin Naz, Marek Pagáč, Saifur Rahman and Rehan Khan
Nanomaterials 2022, 12(12), 2122; https://doi.org/10.3390/nano12122122 - 20 Jun 2022
Cited by 8 | Viewed by 1716
Abstract
Zinc oxide (ZnO) nanoparticles were loaded over non-thermal plasma (P1) and citric acid (P2)-functionalized cotton fabrics using a room temperature sonification process. The cotton samples were pretreated with dielectric barrier discharge (DBD) plasma and citric acid to introduce some reactive moieties on the [...] Read more.
Zinc oxide (ZnO) nanoparticles were loaded over non-thermal plasma (P1) and citric acid (P2)-functionalized cotton fabrics using a room temperature sonification process. The cotton samples were pretreated with dielectric barrier discharge (DBD) plasma and citric acid to introduce some reactive moieties on the fabric to enhance the adhesion power of ZnO nanoparticles with an average particle size of 41 nm. The nanoparticles were dispersed homogeneously on the surface of the P1 sample, which enhanced the antibacterial, UV protection and photocatalytic self-cleaning characteristics of ZnO-loaded fabric. The self-cleaning efficiency of P1 and P2 samples was measured to be about 77% and 63%, respectively. The inhibition zones of 5.5 mm and 5.4 mm were produced by sample P1 against E. coli and S. aureusbacteria, respectively, which were slightly higher than the inhibition zones produced by sample P2. The inhibition zone of the samples roughly decreased by 17% after performing 10 wash cycles. The unloaded cotton fabric had a UPF value of 70.02 units and blocking percentage of 70.92% and 76.54% for UVA and UVB radiations, respectively. The UVA-blocking capacity of samples P1 and P2 was 95.27% and 91.22, respectively. Similarly, the UVB blocking capacity was 94.11% and 92.65%, respectively. The pre-coating plasma treatment was found to be helpful in improving the UV-blocking ability of ZnO-loaded cotton fabric. Full article
(This article belongs to the Special Issue Applied Physics and Nanomaterials)
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14 pages, 5959 KiB  
Article
CuxO-Modified Nanoporous Cu Foil as a Self-Supporting Electrode for Supercapacitor and Oxygen Evolution Reaction
by Zhenhan Li, Jianbin Lin, Xin He, Yue Xin, Ping Liang and Chi Zhang
Nanomaterials 2022, 12(12), 2121; https://doi.org/10.3390/nano12122121 - 20 Jun 2022
Cited by 4 | Viewed by 1681
Abstract
Designing and modifying nanoporous metal foils to make them suitable for supercapacitor and catalysis is significant but challenging. In this work, CuxO nanoflakes have been successfully in situ grown on nanoporous Cu foil via a facile electrooxidation method. A Ga-assisted surface [...] Read more.
Designing and modifying nanoporous metal foils to make them suitable for supercapacitor and catalysis is significant but challenging. In this work, CuxO nanoflakes have been successfully in situ grown on nanoporous Cu foil via a facile electrooxidation method. A Ga-assisted surface Ga-Cu alloying–dealloying is adopted to realize the formation of a nanoporous Cu layer on the flexible Cu foil. The following electrooxidation, at a constant potential, modifies the nanoporous Cu layer with CuxO nanoflakes. The optimum CuxO/Cu electrode (O-Cu-2h) delivers the maximum areal capacitance of 0.745 F cm−2 (410.27 F g−1) at 0.2 mA cm−2 and maintains 94.71% of the capacitance after 12,000 cycles. The supercapacitor consisted of the O-Cu-2h as the positive electrode and activated carbon as the negative electrode has an energy density of 24.20 Wh kg−1 and power density of 0.65 kW kg−1. The potential of using the electrode as oxygen evolution reaction catalysts is also investigated. The overpotential of O-Cu-2h at 10 mA cm−2 is 394 mV; however, the long-term stability still needs further improvement. Full article
(This article belongs to the Special Issue Novel Nanoporous Materials for Energy Storage and Conversion)
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27 pages, 3153 KiB  
Review
Recent Progress on Nanomaterials for NO2 Surface Acoustic Wave Sensors
by Livia Alexandra Dinu, Valentin Buiculescu and Angela Mihaela Baracu
Nanomaterials 2022, 12(12), 2120; https://doi.org/10.3390/nano12122120 - 20 Jun 2022
Cited by 4 | Viewed by 2229
Abstract
NO2 gas surface acoustic wave (SAW)sensors are under continuous development due to their high sensitivity, reliability, low cost and room temperature operation. Their integration ability with different receptor nanomaterials assures a boost in the performance of the sensors. Among the most exploited [...] Read more.
NO2 gas surface acoustic wave (SAW)sensors are under continuous development due to their high sensitivity, reliability, low cost and room temperature operation. Their integration ability with different receptor nanomaterials assures a boost in the performance of the sensors. Among the most exploited nano-materials for sensitive detection of NO2 gas molecules are carbon-based nanomaterials, metal oxide semiconductors, quantum dots, and conducting polymers. All these nanomaterials aim to create pores for NO2 gas adsorption or to enlarge the specific surface area with ultra-small nanoparticles that increase the active sites where NO2 gas molecules can diffuse. This review provides a general overview of NO2 gas SAW sensors, with a focus on the different sensors’ configurations and their fabrication technology, on the nanomaterials used as sensitive NO2 layers and on the test methods for gas detection. The synthesis methods of sensing nanomaterials, their functionalization techniques, the mechanism of interaction between NO2 molecules and the sensing nanomaterials are presented and discussed. Full article
(This article belongs to the Special Issue Nanomaterials in Gas Sensors)
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18 pages, 3252 KiB  
Article
Microwave-Assisted Synthesis of Zn2SnO4 Nanostructures for Photodegradation of Rhodamine B under UV and Sunlight
by Ana Rovisco, Maria Morais, Rita Branquinho, Elvira Fortunato, Rodrigo Martins and Pedro Barquinha
Nanomaterials 2022, 12(12), 2119; https://doi.org/10.3390/nano12122119 - 20 Jun 2022
Cited by 5 | Viewed by 2105
Abstract
The contamination of water resources by pollutants resulting from human activities represents a major concern nowadays. One promising alternative to solve this problem is the photocatalytic process, which has demonstrated very promising and efficient results. Oxide nanostructures are interesting alternatives for these applications [...] Read more.
The contamination of water resources by pollutants resulting from human activities represents a major concern nowadays. One promising alternative to solve this problem is the photocatalytic process, which has demonstrated very promising and efficient results. Oxide nanostructures are interesting alternatives for these applications since they present wide band gaps and high surface areas. Among the photocatalytic oxide nanostructures, zinc tin oxide (ZTO) presents itself as an eco-friendly alternative since its composition includes abundant and non-toxic zinc and tin, instead of critical elements. Moreover, ZTO nanostructures have a multiplicity of structures and morphologies possible to be obtained through low-cost solution-based syntheses. In this context, the current work presents an optimization of ZTO nanostructures (polyhedrons, nanoplates, and nanoparticles) obtained by microwave irradiation-assisted hydrothermal synthesis, toward photocatalytic applications. The nanostructures’ photocatalytic activity in the degradation of rhodamine B under both ultraviolet (UV) irradiation and natural sunlight was evaluated. Among the various morphologies, ZTO nanoparticles revealed the best performance, with degradation > 90% being achieved in 60 min under UV irradiation and in 90 min under natural sunlight. The eco-friendly production process and the demonstrated ability of these nanostructures to be used in various water decontamination processes reinforces their sustainability and the role they can play in a circular economy. Full article
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13 pages, 898 KiB  
Article
Ab Initio Study of Graphene/hBN Van der Waals Heterostructures: Effect of Electric Field, Twist Angles and p-n Doping on the Electronic Properties
by Simone Brozzesi, Claudio Attaccalite, Francesco Buonocore, Giacomo Giorgi, Maurizia Palummo and Olivia Pulci
Nanomaterials 2022, 12(12), 2118; https://doi.org/10.3390/nano12122118 - 20 Jun 2022
Cited by 1 | Viewed by 1882
Abstract
In this work, we study the structural and electronic properties of boron nitride bilayers sandwiched between graphene sheets. Different stacking, twist angles, doping, as well as an applied external gate voltage, are reported to induce important changes in the electronic band structure near [...] Read more.
In this work, we study the structural and electronic properties of boron nitride bilayers sandwiched between graphene sheets. Different stacking, twist angles, doping, as well as an applied external gate voltage, are reported to induce important changes in the electronic band structure near the Fermi level. Small electronic lateral gaps of the order of few meV can appear near the Dirac points K. We further discuss how the bandstructures change applying a perpendicular external electric field, showing how its application lifts the degeneracy of the Dirac cones and, in the twisted case, moves their crossing points away from the Fermi energy. Then, we consider the possibility of co-doping, in an asymmetric way, the two external graphene layers. This is a situation that could be realized in heterostructures deposited on a substrate. We show that the co-doping acts as an effective external electric field, breaking the Dirac cones degeneracy. Finally, our work demonstrates how, by playing with field strength and p-n co-doping, it is possible to tune the small lateral gaps, pointing towards a possible application of C/BN sandwich structures as nano-optical terahertz devices. Full article
(This article belongs to the Special Issue Optoelectronic Properties and Applications of Nanomaterials)
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21 pages, 1804 KiB  
Review
Efficacy of Green Cerium Oxide Nanoparticles for Potential Therapeutic Applications: Circumstantial Insight on Mechanistic Aspects
by Maarij Khan, Zia-ur-Rehman Mashwani, Muhammad Ikram, Naveed I. Raja, Azza H. Mohamed, Guogang Ren and Ahmad A. Omar
Nanomaterials 2022, 12(12), 2117; https://doi.org/10.3390/nano12122117 - 20 Jun 2022
Cited by 19 | Viewed by 3567
Abstract
Green synthesized cerium oxide nanoparticles (GS-CeO2 NPs) have a unique size, shape, and biofunctional properties and are decorated with potential biocompatible agents to perform various therapeutic actions, such as antimicrobial, anticancer, antidiabetic, and antioxidant effects and drug delivery, by acquiring various mechanistic [...] Read more.
Green synthesized cerium oxide nanoparticles (GS-CeO2 NPs) have a unique size, shape, and biofunctional properties and are decorated with potential biocompatible agents to perform various therapeutic actions, such as antimicrobial, anticancer, antidiabetic, and antioxidant effects and drug delivery, by acquiring various mechanistic approaches at the molecular level. In this review article, we provide a detailed overview of some of these critical mechanisms, including DNA fragmentation, disruption of the electron transport chain, degradation of chromosomal assemblage, mitochondrial damage, inhibition of ATP synthase activity, inhibition of enzyme catalytic sites, disorganization, disruption, and lipid peroxidation of the cell membrane, and inhibition of various cellular pathways. This review article also provides up-to-date information about the future applications of GS-CeONPs to make breakthroughs in medical sectors for the advancement and precision of medicine and to effectively inform the disease diagnosis and treatment strategies. Full article
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15 pages, 4390 KiB  
Article
UV-Based Advanced Oxidation Processes of Remazol Brilliant Blue R Dye Catalyzed by Carbon Dots
by Inês M. F. Cardoso, Rita M. F. Cardoso, Luís Pinto da Silva and Joaquim C. G. Esteves da Silva
Nanomaterials 2022, 12(12), 2116; https://doi.org/10.3390/nano12122116 - 20 Jun 2022
Cited by 5 | Viewed by 1747
Abstract
UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82−) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at [...] Read more.
UV-based advanced oxidation processes (AOPs) (UV/H2O2 and UV/S2O82−) with a titanium(IV)-doped carbon dot, TiP-CD, as a catalyst were developed for the decomposition of Remazol Brilliant Blue R (Reactive Blue 19), an anthraquinone textile dye (at T = 25 °C and pH = 7). The Ti-CD, with marked catalytic UV properties, was successfully synthesized by the one-pot hydrothermal procedure, using L-cysteine as carbon precursor, ethylenediamine as nitrogen source, PEG (polyethylene glycol) as a capping agent, and titanium(IV) isopropoxide (precursor of TiO2 doping). Contrary to azo dyes (methyl orange, orange II sodium salt, and reactive black 5), which achieved complete degradation in a time interval less than 30 min in the developed AOP systems (UV/H2O2, UV/S2O82−, and UV/TiO2), the RBB-R showed relatively low degradation rates and low discoloration rate constants. In the presence of the catalyzer, the reaction rate significantly increased, and the pseudo-first-order rate constants for the RBB-R discoloration were UV/3.0 mM H2O2/TIP-CD-0.0330 min−1 and UV/1.02 mM S2O82−/TIP-CD-0.0345 min−1. Full article
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10 pages, 16552 KiB  
Article
Electrodeposition of Lithium-Based Upconversion Nanoparticle Thin Films for Efficient Perovskite Solar Cells
by Masfer Alkahtani, Hussam Qasem, Sultan M. Alenzi, Najla Alsofyani, Anfal Alfahd, Abdulaziz Aljuwayr and Philip R. Hemmer
Nanomaterials 2022, 12(12), 2115; https://doi.org/10.3390/nano12122115 - 20 Jun 2022
Cited by 8 | Viewed by 2024
Abstract
In this work, high-quality lithium-based, LiYF4=Yb3+,Er3+ upconversion (UC) thin film was electrodeposited on fluorene-doped tin oxide (FTO) glass for solar cell applications. A complete perovskite solar cell (PSC) was [...] Read more.
In this work, high-quality lithium-based, LiYF4=Yb3+,Er3+ upconversion (UC) thin film was electrodeposited on fluorene-doped tin oxide (FTO) glass for solar cell applications. A complete perovskite solar cell (PSC) was fabricated on top of the FTO glass coated with UC thin film and named (UC-PSC device). The fabricated UC-PSC device demonstrated a higher power conversion efficiency (PCE) of 19.1%, an additional photocurrent, and a better fill factor (FF) of 76% in comparison to the pristine PSC device (PCE = ~16.57%; FF = 71%). Furthermore, the photovoltaic performance of the UC-PSC device was then tested under concentrated sunlight with a power conversion efficiency (PCE) of 24% without cooling system complexity. The reported results open the door toward efficient PSCs for renewable and green energy applications. Full article
(This article belongs to the Special Issue Advanced Nanomaterials for Perovskite Solar Cells)
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18 pages, 19536 KiB  
Article
Classification of Amino Acids Using Hybrid Terahertz Spectrum and an Efficient Channel Attention Convolutional Neural Network
by Bo Wang, Xiaoling Qin, Kun Meng, Liguo Zhu and Zeren Li
Nanomaterials 2022, 12(12), 2114; https://doi.org/10.3390/nano12122114 - 20 Jun 2022
Cited by 5 | Viewed by 1597
Abstract
Terahertz (THz) spectroscopy is the de facto method to study the vibration modes and rotational energy levels of molecules and is a widely used molecular sensor for non-destructive inspection. Here, based on the THz spectra of 20 amino acids, a method that extracts [...] Read more.
Terahertz (THz) spectroscopy is the de facto method to study the vibration modes and rotational energy levels of molecules and is a widely used molecular sensor for non-destructive inspection. Here, based on the THz spectra of 20 amino acids, a method that extracts high-dimensional features from a hybrid spectrum combined with absorption rate and refractive index is proposed. A convolutional neural network (CNN) calibrated by efficient channel attention (ECA) is designed to learn from the high-dimensional features and make classifications. The proposed method achieves an accuracy of 99.9% and 99.2% on two testing datasets, which are 12.5% and 23% higher than the method solely classifying the absorption spectrum. The proposed method also realizes a processing speed of 3782.46 frames per second (fps), which is the highest among all the methods in comparison. Due to the compact size, high accuracy, and high speed, the proposed method is viable for future applications in THz chemical sensors. Full article
(This article belongs to the Special Issue Intelligent Nanomaterials and Nanosystems)
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11 pages, 5163 KiB  
Communication
Nanolayered CoCrFeNi/Graphene Composites with High Strength and Crack Resistance
by Xiaobin Feng, Ke Cao, Xiege Huang, Guodong Li and Yang Lu
Nanomaterials 2022, 12(12), 2113; https://doi.org/10.3390/nano12122113 - 20 Jun 2022
Cited by 5 | Viewed by 1891
Abstract
Emerging high-entropy alloy (HEA) films achieve high strength but generally show ineludible brittle fractures, strongly restricting their micro/nano-mechanical and functional applications. Nanolayered (NL) CoCrFeNi/graphene composites are elaborately fabricated via magnetron sputtering and the transfer process. It is uncovered that NL CoCrFeNi/graphene composite pillars [...] Read more.
Emerging high-entropy alloy (HEA) films achieve high strength but generally show ineludible brittle fractures, strongly restricting their micro/nano-mechanical and functional applications. Nanolayered (NL) CoCrFeNi/graphene composites are elaborately fabricated via magnetron sputtering and the transfer process. It is uncovered that NL CoCrFeNi/graphene composite pillars exhibit a simultaneous ultra-high strength of 4.73 GPa and considerable compressive plasticity of over 20%. Detailed electron microscope observations and simulations reveal that the monolayer graphene interface can effectively block the crack propagation and stimulate dislocations to accommodate further deformation. Our findings open avenues for the fabrication of high-performance, HEA-based composites, thereby addressing the challenges and unmet needs in flexible electronics and mechanical metamaterials. Full article
(This article belongs to the Special Issue Current Review in Nanofabrication and Nanomanufacturing)
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12 pages, 3726 KiB  
Article
Double Perovskite Ba2LaTaO6 for Ultrafast Fiber Lasers in Anomalous and Normal Net Dispersion Regime
by Yiqing Shu, Mingqi An, Penglai Guo, Xun Yuan, Leiming Wu, Zhitao Lin, Weicheng Chen, Xiaohui Li and Jianqing Li
Nanomaterials 2022, 12(12), 2112; https://doi.org/10.3390/nano12122112 - 20 Jun 2022
Cited by 4 | Viewed by 1436
Abstract
Double perovskites (DPs) have been attracting attention in an assortment of optoelectronic applications, for they hold advantages such as high quantum efficiency, long carrier migration distance and strong linear and nonlinear absorptions. As specific kinds of perovskites (PVKs), DPs are gifted with orthorhombic [...] Read more.
Double perovskites (DPs) have been attracting attention in an assortment of optoelectronic applications, for they hold advantages such as high quantum efficiency, long carrier migration distance and strong linear and nonlinear absorptions. As specific kinds of perovskites (PVKs), DPs are gifted with orthorhombic crystal structures which provide rich conversion combinations and broaden the space for research and application. However, few works have been reported about DPs in ultrafast photonics applications. In this article, a DP with chemical formula of Ba2LaTaO6 (BLT) was successfully synthesized by high-temperature solid phase method. The microstructures and morphologies were observed, and the linear and nonlinear absorption were characterized. By first using BLT as a novel saturable absorber in both normal and anomalous dispersion region fiber lasers, dual-wavelength soliton and dissipative soliton were successfully operated at C-band. This study affirms BLT’s nonlinear optical properties, lays the foundation for optical research on BLT, and meanwhile provides a meaningful reference for future development of pulsed lasers based on DPs. Full article
(This article belongs to the Special Issue Molecular Beam Epitaxy Growth of Quantum Wires and Quantum Dots)
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17 pages, 3243 KiB  
Review
Recent Progress on Nanocrystalline Metallic Materials for Biomedical Applications
by Huafang Li, Pengyu Wang and Cuie Wen
Nanomaterials 2022, 12(12), 2111; https://doi.org/10.3390/nano12122111 - 19 Jun 2022
Cited by 15 | Viewed by 2126
Abstract
Nanocrystalline (NC) metallic materials have better mechanical properties, corrosion behavior and biocompatibility compared with their coarse-grained (CG) counterparts. Recently, nanocrystalline metallic materials are receiving increasing attention for biomedical applications. In this review, we have summarized the mechanical properties, corrosion behavior, biocompatibility, and clinical [...] Read more.
Nanocrystalline (NC) metallic materials have better mechanical properties, corrosion behavior and biocompatibility compared with their coarse-grained (CG) counterparts. Recently, nanocrystalline metallic materials are receiving increasing attention for biomedical applications. In this review, we have summarized the mechanical properties, corrosion behavior, biocompatibility, and clinical applications of different types of NC metallic materials. Nanocrystalline materials, such as Ti and Ti alloys, shape memory alloys (SMAs), stainless steels (SS), and biodegradable Fe and Mg alloys prepared by high-pressure torsion, equiangular extrusion techniques, etc., have better mechanical properties, superior corrosion resistance and biocompatibility properties due to their special nanostructures. Moreover, future research directions of NC metallic materials are elaborated. This review can provide guidance and reference for future research on nanocrystalline metallic materials for biomedical applications. Full article
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12 pages, 2802 KiB  
Article
Artificial Synapse Consisted of TiSbTe/SiCx:H Memristor with Ultra-high Uniformity for Neuromorphic Computing
by Liangliang Chen, Zhongyuan Ma, Kangmin Leng, Tong Chen, Hongsheng Hu, Yang Yang, Wei Li, Jun Xu, Ling Xu and Kunji Chen
Nanomaterials 2022, 12(12), 2110; https://doi.org/10.3390/nano12122110 - 19 Jun 2022
Cited by 2 | Viewed by 1824
Abstract
To enable a-SiCx:H-based memristors to be integrated into brain-inspired chips, and to efficiently deal with the massive and diverse data, high switching uniformity of the a-SiC0.11:H memristor is urgently needed. In this study, we introduced a TiSbTe layer into [...] Read more.
To enable a-SiCx:H-based memristors to be integrated into brain-inspired chips, and to efficiently deal with the massive and diverse data, high switching uniformity of the a-SiC0.11:H memristor is urgently needed. In this study, we introduced a TiSbTe layer into an a-SiC0.11:H memristor, and successfully observed the ultra-high uniformity of the TiSbTe/a-SiC0.11:H memristor device. Compared with the a-SiC0.11:H memristor, the cycle-to-cycle coefficient of variation in the high resistance state and the low resistance state of TiSbTe/a-SiC0.11:H memristors was reduced by 92.5% and 66.4%, respectively. Moreover, the device-to-device coefficient of variation in the high resistance state and the low resistance state of TiSbTe/a-SiC0.11:H memristors decreased by 93.6% and 86.3%, respectively. A high-resolution transmission electron microscope revealed that a permanent TiSbTe nanocrystalline conductive nanofilament was formed in the TiSbTe layer during the DC sweeping process. The localized electric field of the TiSbTe nanocrystalline was beneficial for confining the position of the conductive filaments in the a-SiC0.11:H film, which contributed to improving the uniformity of the device. The temperature-dependent I-V characteristic further confirmed that the bridge and rupture of the Si dangling bond nanopathway was responsible for the resistive switching of the TiSbTe/a-SiC0.11:H device. The ultra-high uniformity of the TiSbTe/a-SiC0.11:H device ensured the successful implementation of biosynaptic functions such as spike-duration-dependent plasticity, long-term potentiation, long-term depression, and spike-timing-dependent plasticity. Furthermore, visual learning capability could be simulated through changing the conductance of the TiSbTe/a-SiC0.11:H device. Our discovery of the ultra-high uniformity of TiSbTe/a-SiC0.11:H memristor devices provides an avenue for their integration into the next generation of AI chips. Full article
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9 pages, 2675 KiB  
Article
Influence of Structural Parameters on Performance of SAW Resonators Based on 128° YX LiNbO3 Single Crystal
by Wenping Geng, Caiqin Zhao, Feng Xue, Xiaojun Qiao, Jinlong He, Gang Xue, Yukai Liu, Huifen Wei, Kaixi Bi, Linyu Mei and Xiujian Chou
Nanomaterials 2022, 12(12), 2109; https://doi.org/10.3390/nano12122109 - 19 Jun 2022
Cited by 9 | Viewed by 2001
Abstract
The seeking of resonator with high Q and low insertion loss is attractive for critical sensing scenes based on the surface acoustic wave (SAW). In this work, 128° YX LiNbO3-based SAW resonators were utilized to optimize the output performance through IDT [...] Read more.
The seeking of resonator with high Q and low insertion loss is attractive for critical sensing scenes based on the surface acoustic wave (SAW). In this work, 128° YX LiNbO3-based SAW resonators were utilized to optimize the output performance through IDT structure parameters. Once the pairs of IDTs, the acoustic aperture, the reflecting grid logarithm, and the gap between IDT and reflector are changed, a better resonance frequency of 224.85 MHz and a high Q of 1364.5 were obtained. All the results demonstrate the structure parameters design is helpful for the performance enhancement with regard to SAW resonators, especially for designing and fabricating high-Q devices. Full article
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11 pages, 2040 KiB  
Article
Naringenin Ultrafine Powder Was Prepared by a New Anti-Solvent Recrystallization Method
by Xiaonan Zhang, Yan Huang, Yufei Shi, Mengyu Chen, Lubin Zhang, Yimin An and Zhiwei Liu
Nanomaterials 2022, 12(12), 2108; https://doi.org/10.3390/nano12122108 - 19 Jun 2022
Cited by 7 | Viewed by 1562
Abstract
Raw naringenin directly isolated from plants is significantly limited by its poor dissolution rate and low bioavailability for clinical and in vivo studies. This study reported a method for the preparation of naringenin ultrafine powder (NUP) using a novel anti-solvent recrystallization process; preliminary [...] Read more.
Raw naringenin directly isolated from plants is significantly limited by its poor dissolution rate and low bioavailability for clinical and in vivo studies. This study reported a method for the preparation of naringenin ultrafine powder (NUP) using a novel anti-solvent recrystallization process; preliminary experiments were conducted using six single-factor experiments. The response surface Box–Behnken (BBD) design was used to optimize the level of factors. The optimal preparation conditions of the DMP were obtained as follows: the feed rate was 40.82 mL/min, the solution concentration was 20.63 mg/mL, and the surfactant ratio was 0.62%. The minimum average particle size was 305.58 ± 0.37 nm in the derived optimum conditions. A scanning electron microscope was used to compare and analyze the appearance and morphology of the powder before and after preparation. The characterization results of FTIR, TG and XRD showed that no chemical change occurred in the powder before and after preparation. Through the simulated gastrointestinal juice digestion experiment, it was confirmed that the absorption rate of NUP was 2.96 times and 4.05 times higher than raw naringenin, respectively. Therefore, the results showed that the reduction in the particle size through the use of low-speed recrystallization could improve the absorption rate and provided a feasible approach for the further applications. Full article
(This article belongs to the Topic Microfluidics Applied in Nanomedicine and Pharmaceutics)
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12 pages, 5027 KiB  
Article
Tunable Emission and Color Temperature of Yb3+/Er3+/Tm3+-Tridoped Y2O3-ZnO Ceramic Nano-Phosphors Using Er3+ Concentration and Excitation Pump Power
by Boxu Xu, Chao Song, Jie Song, Rui Huang, Zhenxu Lin, Yi Zhang, Shaomin Lin, Yanqing Guo, Guangxu Chen and Jun Song
Nanomaterials 2022, 12(12), 2107; https://doi.org/10.3390/nano12122107 - 19 Jun 2022
Cited by 2 | Viewed by 1391
Abstract
In this study, a series of well-crystallized Yb3+/Er3+/Tm3+-tridoped Y2O3-ZnO ceramic nano-phosphors were prepared using sol–gel synthesis, and the phosphor structures were studied using X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The phosphors [...] Read more.
In this study, a series of well-crystallized Yb3+/Er3+/Tm3+-tridoped Y2O3-ZnO ceramic nano-phosphors were prepared using sol–gel synthesis, and the phosphor structures were studied using X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The phosphors were well crystallized and exhibited a sharp-edged angular crystal structure and mesoporous structure consisting of 270 nm nano-particles. All phosphors generated blue, green, and red emission bands attributed to Tm: 1G43H6, Er: 2H11/2 (4S3/2)→4I15/2, and Er: 4F9/24I15/2 radiative transitions, respectively. Increasing in luminescent centers, weakening of lattice symmetry, and releasing of dormant rare earth ions can enhance all emissions. Er3+ can obtain energy from Tm3+ to enhance green and red emission. These colors can be tuned by optimizing the doping concentrations of the Er3+ ion. The color coordinates were adjusted by tuning both the Er3+ concentration and excitation laser pump power to shift the color coordinates and correlated color temperature. The findings of this study will broaden the potential practical applications of phosphors. Full article
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10 pages, 7327 KiB  
Article
Self-Templating Synthesis of N/P/Fe Co-Doped 3D Porous Carbon for Oxygen Reduction Reaction Electrocatalysts in Alkaline Media
by Yan Rong and Siping Huang
Nanomaterials 2022, 12(12), 2106; https://doi.org/10.3390/nano12122106 - 19 Jun 2022
Cited by 7 | Viewed by 1563
Abstract
The development of low-cost, highly active, and stable oxygen reduction reaction (ORR) catalysts is of great importance for practical applications in numerous energy conversion devices. Herein, iron/nitrogen/phosphorus co-doped carbon electrocatalysts (NPFe-C) with multistage porous structure were synthesized by the self-template method using melamine, [...] Read more.
The development of low-cost, highly active, and stable oxygen reduction reaction (ORR) catalysts is of great importance for practical applications in numerous energy conversion devices. Herein, iron/nitrogen/phosphorus co-doped carbon electrocatalysts (NPFe-C) with multistage porous structure were synthesized by the self-template method using melamine, phytic acid and ferric trichloride as precursors. In an alkaline system, the ORR half-wave potential is 0.867 V (vs. RHE), comparable to that of platinum-based catalysts. It is noteworthy that NPFe-C performs better than the commercial Pt/C catalyst in terms of power density and specific capacity. Its unique structure and the feature of heteroatom doping endow the catalyst with higher mass transfer ability and abundant available active sites, and the improved performance can be attributed to the following aspects: (1) Fe-, N-, and P triple doping created abundant active sites, contributing to the higher intrinsic activity of catalysts. (2) Phytic acid was crosslinked with melamine to form hydrogel, and its carbonized products have high specific surface area, which is beneficial for a large number of active sites to be exposed at the reaction interface. (3) The porous three-dimensional carbon network facilitates the transfer of reactants/intermediates/products and electric charge. Therefore, Fe/N/P Co-doped 3D porous carbon materials prepared by a facile and scalable pyrolysis route exhibit potential in the field of energy conversion/storage. Full article
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25 pages, 7899 KiB  
Article
Effect of Conducting, Semi-Conducting and Insulating Nanoparticles on AC Breakdown Voltage and Partial Discharge Activity of Synthetic Ester: A Statistical Analysis
by Hocine Khelifa, Abderrahmane Beroual and Eric Vagnon
Nanomaterials 2022, 12(12), 2105; https://doi.org/10.3390/nano12122105 - 19 Jun 2022
Cited by 14 | Viewed by 1496
Abstract
This paper is aimed at studying the influence of conducting (Fe3O4), semi-conductive (ZnO), and insulating (ZrO2, SiO2, and Al2O3) nanoparticles (NPs) at various concentrations on the AC dielectric strength of MIDEL [...] Read more.
This paper is aimed at studying the influence of conducting (Fe3O4), semi-conductive (ZnO), and insulating (ZrO2, SiO2, and Al2O3) nanoparticles (NPs) at various concentrations on the AC dielectric strength of MIDEL 7131 synthetic ester (SE) and partial discharges activity. First, a detailed and improved procedure for preparing nanofluids (NFs) in five concentrations ranging from 0.1 g/L to 0.5 g/L is presented, including high-speed agitation and ultrasonication. Then, the long-term stability is checked based on zeta potential analysis. After preparing and characterizing the NF samples, the following step is to measure their AC breakdown voltage (BDV). Due to the limitation of the high voltage supply (Baur system), the tests are performed according to IEC 60156 standard (2.5 mm gap distance) only with ZnO, ZrO2, and SiO2 NPs, and for comparison, tests are executed for all considered NPs with an electrodes gap of 2 mm. It is shown that the addition of Fe3O4 (20 nm), ZnO (25 nm), ZrO2 (20–30 nm), SiO2 (10–20 nm), Al2O3 (20–30 nm), and Al2O3 (50 nm) NPs improves the dielectric strength of synthetic ester upon an optimal concentration which gives the highest AC BDV. SiO2 (10–20 nm) and Al2O3 (20–30 nm) manifest their best improvement at 0.3 g/L, while for the other NFs, the best improvement is observed at 0.4 g/L. Further, the Anderson–Darling goodness-of-fit test is performed on the experimental data to check their conformity with the Extreme value (EV), normal, and Weibull distributions; the normal and EV fit curves are plotted and used to evaluate the breakdown voltages at probabilities of 1%, 10%, and 50%. It is shown that the AC breakdown voltage outcomes for most investigated nanofluids mostly obey the three EV, normal, and Weibull distributions. Then, the best combinations (nature of NP and optimal concentration), namely Fe3O4 (20 nm, 0.4 g/L), Al2O3 (20–30 nm, 0.3 g/L), and Al2O3 (50 nm, 0.4 g/L) NPs, that highly enhance the AC BDV of SE are chosen for a partial discharge activity investigation and comparison with pure SE. It is shown that the addition of those NPs significantly reduces the activity of partial discharges compared to pure SE. Full article
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14 pages, 3632 KiB  
Article
Zn and Zn-Fe Nanostructures with Multifunctional Properties as Components for Food Packaging Materials
by Hafsae Lamsaf, Lina F. Ballesteros, Miguel A. Cerqueira, José A. Teixeira, Lorenzo M. Pastrana, Luís Rebouta, Sandra Carvalho and Sebastian Calderon
Nanomaterials 2022, 12(12), 2104; https://doi.org/10.3390/nano12122104 - 18 Jun 2022
Viewed by 1815
Abstract
Metallic and bimetallic nanostructures have shown interesting chromatic and antibacterial properties, and they can be used in various applications. In this work, zinc (Zn) and iron (Fe) nanostructures were produced with different morphologies: (i) pure Zn; (ii) Zn-Fe nanoalloys; (iii) Zn-Fe nanolayers (Zn-Fe [...] Read more.
Metallic and bimetallic nanostructures have shown interesting chromatic and antibacterial properties, and they can be used in various applications. In this work, zinc (Zn) and iron (Fe) nanostructures were produced with different morphologies: (i) pure Zn; (ii) Zn-Fe nanoalloys; (iii) Zn-Fe nanolayers (Zn-Fe NLs); and (iv) Zn nanolayers combined with Fe nanoparticles (Zn NLs + Fe NPs). The aim was to produce components for food packaging materials with active and intelligent properties, including oxygen absorption capacity, chromatic properties, and antibacterial properties. Thus, the morphology, structure, and chemical composition of the samples were characterized and correlated with their oxidation, chromatic, and antibacterial properties. The results revealed a relevant reduction in the coating’s opacity after oxidation varying from 100 to 10% depending on the morphology of the system. All coatings exhibited significant antibacterial activity against S. aureus, revealing a direct correlation with Zn content. The incorporation of Fe for all atomic arrangements showed a negative impact on the antibacterial effect against E. coli, decreasing to less than half the zone of inhibition for Zn-Fe NLs and Zn NLs + Fe NPs and suppressing the antibacterial effect for Zn-Fe alloy when compared with the pure Zn system. Full article
(This article belongs to the Section Nanocomposite Materials)
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29 pages, 6746 KiB  
Review
A Review of Advancing Two-Dimensional Material Membranes for Ultrafast and Highly Selective Liquid Separation
by Hongli Zhang, Yiling Zheng, Shuwen Yu, Weixing Chen and Jie Yang
Nanomaterials 2022, 12(12), 2103; https://doi.org/10.3390/nano12122103 - 18 Jun 2022
Cited by 12 | Viewed by 3098
Abstract
Membrane-based nanotechnology possesses high separation efficiency, low economic and energy consumption, continuous operation modes and environmental benefits, and has been utilized in various separation fields. Two-dimensional nanomaterials (2DNMs) with unique atomic thickness have rapidly emerged as ideal building blocks to develop high-performance separation [...] Read more.
Membrane-based nanotechnology possesses high separation efficiency, low economic and energy consumption, continuous operation modes and environmental benefits, and has been utilized in various separation fields. Two-dimensional nanomaterials (2DNMs) with unique atomic thickness have rapidly emerged as ideal building blocks to develop high-performance separation membranes. By rationally tailoring and precisely controlling the nanochannels and/or nanoporous apertures of 2DNMs, 2DNM-based membranes are capable of exhibiting unprecedentedly high permeation and selectivity properties. In this review, the latest breakthroughs in using 2DNM-based membranes as nanosheets and laminar membranes are summarized, including their fabrication, structure design, transport behavior, separation mechanisms, and applications in liquid separations. Examples of advanced 2D material (graphene family, 2D TMDs, MXenes, metal–organic frameworks, and covalent organic framework nanosheets) membrane designs with remarkably perm-selective properties are highlighted. Additionally, the development of strategies used to functionalize membranes with 2DNMs are discussed. Finally, current technical challenges and emerging research directions of advancing 2DNM membranes for liquid separation are shared. Full article
(This article belongs to the Special Issue Nanomaterials for Sustainable Energy and Environmental Protection)
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21 pages, 4920 KiB  
Review
Application of Quantum Dot Interface Modification Layer in Perovskite Solar Cells: Progress and Perspectives
by Yankai Zhou, Xingrui Luo, Jiayan Yang, Qingqing Qiu, Tengfeng Xie and Tongxiang Liang
Nanomaterials 2022, 12(12), 2102; https://doi.org/10.3390/nano12122102 - 18 Jun 2022
Cited by 14 | Viewed by 3091
Abstract
Perovskite solar cells (PSCs) are currently attracting a great deal of attention for their excellent photovoltaic properties, with a maximum photoelectric conversion efficiency (PCE) of 25.5%, comparable to that of silicon-based solar cells. However, PSCs suffer from energy level mismatch, a large number [...] Read more.
Perovskite solar cells (PSCs) are currently attracting a great deal of attention for their excellent photovoltaic properties, with a maximum photoelectric conversion efficiency (PCE) of 25.5%, comparable to that of silicon-based solar cells. However, PSCs suffer from energy level mismatch, a large number of defects in perovskite films, and easy decomposition under ultraviolet (UV) light, which greatly limit the industrial application of PSCs. Currently, quantum dot (QD) materials are widely used in PSCs due to their properties, such as quantum size effect and multi-exciton effect. In this review, we detail the application of QDs as an interfacial layer to PSCs to optimize the energy level alignment between two adjacent layers, facilitate charge and hole transport, and also effectively assist in the crystallization of perovskite films and passivate defects on the film surface. Full article
(This article belongs to the Special Issue Solar Thin Film Nanomaterials and Nanodevices)
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9 pages, 3867 KiB  
Article
A Novel Crossbeam Structure with Graphene Sensing Element for N/MEMS Mechanical Sensors
by Junqiang Wang, Zehua Zhu, Yue Qi and Mengwei Li
Nanomaterials 2022, 12(12), 2101; https://doi.org/10.3390/nano12122101 - 18 Jun 2022
Cited by 5 | Viewed by 1742
Abstract
A graphene membrane acts as a highly sensitive element in a nano/micro–electro–mechanical system (N/MEMS) due to its unique physical and chemical properties. Here, a novel crossbeam structure with a graphene varistor protected by Si3N4 is presented for N/MEMS mechanical sensors. [...] Read more.
A graphene membrane acts as a highly sensitive element in a nano/micro–electro–mechanical system (N/MEMS) due to its unique physical and chemical properties. Here, a novel crossbeam structure with a graphene varistor protected by Si3N4 is presented for N/MEMS mechanical sensors. It substantially overcomes the poor reliability of previous sensors with suspended graphene and exhibits excellent mechanoelectrical coupling performance, as graphene is placed on the root of the crossbeam. By performing basic mechanical electrical measurements, a preferable gauge factor of ~1.35 is obtained. The sensitivity of the graphene pressure sensor based on the crossbeam structure chip is 33.13 mV/V/MPa in a wide range of 0~20 MPa. Other static specifications, including hysteresis error, nonlinear error, and repeatability error, are 2.0119%, 3.3622%, and 4.0271%, respectively. We conclude that a crossbeam structure with a graphene sensing element can be an application for the N/MEMS mechanical sensor. Full article
(This article belongs to the Special Issue Functional Graphene-Based Nanodevices)
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34 pages, 4016 KiB  
Review
2D Material and Perovskite Heterostructure for Optoelectronic Applications
by Sijia Miao, Tianle Liu, Yujian Du, Xinyi Zhou, Jingnan Gao, Yichu Xie, Fengyi Shen, Yihua Liu and Yuljae Cho
Nanomaterials 2022, 12(12), 2100; https://doi.org/10.3390/nano12122100 - 18 Jun 2022
Cited by 13 | Viewed by 4279
Abstract
Optoelectronic devices are key building blocks for sustainable energy, imaging applications, and optical communications in modern society. Two-dimensional materials and perovskites have been considered promising candidates in this research area due to their fascinating material properties. Despite the significant progress achieved in the [...] Read more.
Optoelectronic devices are key building blocks for sustainable energy, imaging applications, and optical communications in modern society. Two-dimensional materials and perovskites have been considered promising candidates in this research area due to their fascinating material properties. Despite the significant progress achieved in the past decades, challenges still remain to further improve the performance of devices based on 2D materials or perovskites and to solve stability issues for their reliability. Recently, a novel concept of 2D material/perovskite heterostructure has demonstrated remarkable achievements by taking advantage of both materials. The diverse fabrication techniques and large families of 2D materials and perovskites open up great opportunities for structure modification, interface engineering, and composition tuning in state-of-the-art optoelectronics. In this review, we present comprehensive information on the synthesis methods, material properties of 2D materials and perovskites, and the research progress of optoelectronic devices, particularly solar cells and photodetectors which are based on 2D materials, perovskites, and 2D material/perovskite heterostructures with future perspectives. Full article
(This article belongs to the Special Issue 2D Nanostructures for Optoelectronic and Green Energy Devices)
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23 pages, 4582 KiB  
Article
Potassium Chloroaurate-Mediated In Vitro Synthesis of Gold Nanoparticles Improved Root Growth by Crosstalk with Sucrose and Nutrient-Dependent Auxin Homeostasis in Arabidopsis thaliana
by Sandeep Yadav, Poli Yugandhar, Hemasundar Alavilli, Ramesh Raliya, Archita Singh, Shivendra V. Sahi, Ananda K. Sarkar and Ajay Jain
Nanomaterials 2022, 12(12), 2099; https://doi.org/10.3390/nano12122099 - 18 Jun 2022
Cited by 1 | Viewed by 1740
Abstract
In a hydroponic system, potassium chloroaurate (KAuCl4) triggers the in vitro sucrose (Suc)-dependent formation of gold nanoparticles (AuNPs). AuNPs stimulate the growth of the root system, but their molecular mechanism has not been deciphered. The root system of Arabidopsis (Arabidopsis [...] Read more.
In a hydroponic system, potassium chloroaurate (KAuCl4) triggers the in vitro sucrose (Suc)-dependent formation of gold nanoparticles (AuNPs). AuNPs stimulate the growth of the root system, but their molecular mechanism has not been deciphered. The root system of Arabidopsis (Arabidopsis thaliana) exhibits developmental plasticity in response to the availability of various nutrients, Suc, and auxin. Here, we showed the roles of Suc, phosphorus (P), and nitrogen (N) in facilitating a AuNPs-mediated increase in root growth. Furthermore, the recuperating effects of KAuCl4 on the natural (IAA) auxin-mediated perturbation of the root system were demonstrated. Arabidopsis seedlings harboring the cell division marker CycB1;1::CDB-GUS provided evidence of the restoration efficacy of KAuCl4 on the IAA-mediated inhibitory effect on meristematic cell proliferation of the primary and lateral roots. Arabidopsis harboring synthetic auxin DR5rev::GFP exhibited a reinstating effect of KAuCl4 on IAA-mediated aberration in auxin subcellular localization in the root. KAuCl4 also exerted significant and differential recuperating effects on the IAA-mediated altered expression of the genes involved in auxin signaling and biosynthetic pathways in roots. Our results highlight the crosstalk between KAuCl4-mediated improved root growth and Suc and nutrient-dependent auxin homeostasis in Arabidopsis. Full article
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20 pages, 1742 KiB  
Article
Application of the Higher-Order Hamilton Approach to the Nonlinear Free Vibrations Analysis of Porous FG Nano-Beams in a Hygrothermal Environment Based on a Local/Nonlocal Stress Gradient Model of Elasticity
by Rosa Penna, Luciano Feo, Giuseppe Lovisi and Francesco Fabbrocino
Nanomaterials 2022, 12(12), 2098; https://doi.org/10.3390/nano12122098 - 17 Jun 2022
Cited by 10 | Viewed by 1626
Abstract
Nonlinear transverse free vibrations of porous functionally-graded (FG) Bernoulli–Euler nanobeams in hygrothermal environments through the local/nonlocal stress gradient theory of elasticity were studied. By using the Galerkin method, the governing equations were reduced to a nonlinear ordinary differential equation. The closed form analytical [...] Read more.
Nonlinear transverse free vibrations of porous functionally-graded (FG) Bernoulli–Euler nanobeams in hygrothermal environments through the local/nonlocal stress gradient theory of elasticity were studied. By using the Galerkin method, the governing equations were reduced to a nonlinear ordinary differential equation. The closed form analytical solution of the nonlinear natural flexural frequency was then established using the higher-order Hamiltonian approach to nonlinear oscillators. A numerical investigation was developed to analyze the influence of different parameters both on the thermo-elastic material properties and the structural response, such as material gradient index, porosity volume fraction, nonlocal parameter, gradient length parameter, mixture parameter, and the amplitude of the nonlinear oscillator on the nonlinear flexural vibrations of metal–ceramic FG porous Bernoulli–Euler nano-beams. Full article
(This article belongs to the Special Issue Computational Study of Nanomaterials)
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26 pages, 3433 KiB  
Review
Dynamic and Active THz Graphene Metamaterial Devices
by Lan Wang, Ning An, Xusheng He, Xinfeng Zhang, Ao Zhu, Baicheng Yao and Yaxin Zhang
Nanomaterials 2022, 12(12), 2097; https://doi.org/10.3390/nano12122097 - 17 Jun 2022
Cited by 14 | Viewed by 3166
Abstract
In recent years, terahertz waves have attracted significant attention for their promising applications. Due to a broadband optical response, an ultra-fast relaxation time, a high nonlinear coefficient of graphene, and the flexible and controllable physical characteristics of its meta-structure, graphene metamaterial has been [...] Read more.
In recent years, terahertz waves have attracted significant attention for their promising applications. Due to a broadband optical response, an ultra-fast relaxation time, a high nonlinear coefficient of graphene, and the flexible and controllable physical characteristics of its meta-structure, graphene metamaterial has been widely explored in interdisciplinary frontier research, especially in the technologically important terahertz (THz) frequency range. Here, graphene’s linear and nonlinear properties and typical applications of graphene metamaterial are reviewed. Specifically, the discussion focuses on applications in optically and electrically actuated terahertz amplitude, phase, and harmonic generation. The review concludes with a brief examination of potential prospects and trends in graphene metamaterial. Full article
(This article belongs to the Special Issue Advances in Stimuli-Responsive Nanomaterials)
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16 pages, 5932 KiB  
Article
Facile Synthesized Cu–RGO and Ag–RGO Nanocomposites with Potential Biomedical Applications
by Diana Kichukova, Ivanka Spassova, Aneliya Kostadinova, Anna Staneva and Daniela Kovacheva
Nanomaterials 2022, 12(12), 2096; https://doi.org/10.3390/nano12122096 - 17 Jun 2022
Cited by 13 | Viewed by 1765
Abstract
In the present study, we report on the facile prepared nanocomposites of reduced graphene oxide RGO with Cu and Ag. The synthesis was performed through an environmentally friendly and easy method by simultaneous reduction in solutions containing Cu2+ or Ag+ and [...] Read more.
In the present study, we report on the facile prepared nanocomposites of reduced graphene oxide RGO with Cu and Ag. The synthesis was performed through an environmentally friendly and easy method by simultaneous reduction in solutions containing Cu2+ or Ag+ and graphene oxide (GO) using zinc powder as a reducing agent in aqueous acidic media. The composites are characterized by powder X-ray diffraction, low-temperature nitrogen adsorption, X-ray photoelectron and FTIR and Raman spectroscopies, as well as Scanning and Transmission electron microscopies. The antibacterial activity of the composites was tested for Staphylococcus aureus, Escherichia coli and antifungal activity for Candida albicans. The cytotoxicity of the materials was studied towards two types of eukaryotic cells—MDCK II and A549 cell lines. The composites obtained consist of homogeneously distributed Cu and Ag nanoparticles on the surface of graphene sheets and manifest good antimicrobial activity and high cytotoxicity. The results clearly show that both metal–RGO composites can be successfully used as antimicrobial and anticancer agents. Full article
(This article belongs to the Section Nanocomposite Materials)
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19 pages, 1740 KiB  
Article
Intrinsic Multienzyme-like Activities of the Nanoparticles of Mn and Fe Cyano-Bridged Assemblies
by Yunong Zhang, David Kudriashov, Liubov Pershina, Andreas Offenhäusser and Yulia Mourzina
Nanomaterials 2022, 12(12), 2095; https://doi.org/10.3390/nano12122095 - 17 Jun 2022
Cited by 4 | Viewed by 1678
Abstract
This study investigates the intrinsic multienzyme-like properties of the non-stabilized nanocrystalline nanoparticles of manganese-doped Prussian blue (Mn-PB) nanozymes and Prussian blue (PB) nanozymes in chemical and electrocatalytic transformations of reactive oxygen species. The effect of manganese doping on the structural, biomimetic, and electrocatalytic [...] Read more.
This study investigates the intrinsic multienzyme-like properties of the non-stabilized nanocrystalline nanoparticles of manganese-doped Prussian blue (Mn-PB) nanozymes and Prussian blue (PB) nanozymes in chemical and electrocatalytic transformations of reactive oxygen species. The effect of manganese doping on the structural, biomimetic, and electrocatalytic properties of cyano-bridged assemblies is also discussed. Full article
(This article belongs to the Topic Catalytic Applications of Transition Metals)
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