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Nanomaterials, Volume 13, Issue 7 (April-1 2023) – 157 articles

Cover Story (view full-size image): The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labeled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspective. The results reported here on hexylimidazolium-based POSS further deepen the knowledge of QAS formulations. View this paper
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12 pages, 10257 KiB  
Article
In Situ Nano-SiO2 Electrospun Polyethylene-Oxide-Based Nano-Fiber Composite Solid Polymer Electrolyte for High-Performance Lithium-Ion Batteries
by Luwei Shi, Longxing Zhang, Yanping Yang, Haipeng Zhang, Ruijie Yao, Caoquan Yuan and Shaobo Cheng
Nanomaterials 2023, 13(7), 1294; https://doi.org/10.3390/nano13071294 - 06 Apr 2023
Cited by 3 | Viewed by 1677
Abstract
Polyethylene oxide (PEO)-based composite polymer electrolytes (CPEs) containing in situ SiO2 fillers are prepared using an electrostatic spinning method at room temperature. Through the in situ hydrolysis of tetraethyl silicate (TEOS), the generated SiO2 nanospheres are uniformly dispersed in the PEO [...] Read more.
Polyethylene oxide (PEO)-based composite polymer electrolytes (CPEs) containing in situ SiO2 fillers are prepared using an electrostatic spinning method at room temperature. Through the in situ hydrolysis of tetraethyl silicate (TEOS), the generated SiO2 nanospheres are uniformly dispersed in the PEO matrix to form a 3D ceramic network, which enhances the mechanical properties of the electrolyte as a reinforcing phase. The interaction between SiO2 nanospheres and PEO chains results in chemical bonding with a decrease in the crystallinity of the PEO matrix, as well as the complexation strength of PEO chains with lithium ions during the hydrolysis process. Meanwhile, the addition of SiO2 nanospheres can disturb the orderliness of PEO chain segments and further suppress the crystallization of the PEO matrix. Therefore, improved mechanical/electrochemical properties can be obtained in the as-spun electrolyte with the unique one-dimensional high-speed ion channels. The electrospun CPE with in situ SiO2 (10 wt%, ca. 45 nm) has a higher ionic conductivity of 1.03 × 10−3 S cm−1 than that of the mechanical blending one. Meanwhile, the upper limit of the electrochemical stability window is up to 5.5 V versus Li+/Li, and a lithium-ion migration number can be of up to 0.282 at room temperature. In addition, in situ SiO2 electrospun CPE achieves a tensile strength of 1.12 MPa, elongation at the break of 488.1%, and it has an excellent plasticity. All in all, it is expected that the electrospun CPE prepared in this study is a promising one for application in an all-solid-state lithium-ion battery (LIB) with a high energy density, long life cycle, and high safety. Full article
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12 pages, 2995 KiB  
Article
Two-Dimensional Sb Modified TiO2 Nanorod Arrays as Photoanodes for Efficient Solar Water Splitting
by Jie Gao, Shengqi Zhang, Xiaoqing Ma, Yi Sun and Xiaoyan Zhang
Nanomaterials 2023, 13(7), 1293; https://doi.org/10.3390/nano13071293 - 06 Apr 2023
Cited by 3 | Viewed by 1595
Abstract
As one of the widely studied semiconductor materials, titanium dioxide (TiO2) exhibits high photoelectrochemical (PEC) water-splitting performance as well as high chemical and photo stability. However, limited by a wide band gap and fast electron-hole recombination rate, the low solar-to-hydrogen conversion [...] Read more.
As one of the widely studied semiconductor materials, titanium dioxide (TiO2) exhibits high photoelectrochemical (PEC) water-splitting performance as well as high chemical and photo stability. However, limited by a wide band gap and fast electron-hole recombination rate, the low solar-to-hydrogen conversion efficiency remains a bottleneck for the practical application of TiO2-based photoelectrodes. To improve the charge separation and water oxidation efficiency of TiO2 photoanodes, antimonene, a two-dimensional (2D) material obtained by liquid-phase exfoliation, was assembled onto TiO2 nanorod arrays (TNRAs) by a simple drop-coating assembly process. PEC measurements showed that the resulting 2D Sb/TiO2 photoelectrode displayed an enhanced photocurrent density of about 1.32 mA cm−2 in 1.0 M KOH at 0.3 V vs. Hg/HgO, which is ~1.65 times higher than that of the pristine TNRAs. Through UV-Vis absorption and electrochemical impedance spectroscopy measurements, it was possible to ascribe the enhanced PEC performances of the 2D Sb/TiO2 photoanode to increased absorption intensity in the visible light region, and improved interfacial charge-transfer kinetics in the 2D Sb/TiO2 heterojunction, which promotes electron-hole separation, transfer, and collection. Full article
(This article belongs to the Topic New Materials and Advanced Applications in Photocatalysis)
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12 pages, 4626 KiB  
Article
Efficient Charge Transfer in MAPbI3 QDs/TiO2 Heterojunctions for High-Performance Solar Cells
by Hua Li, Chao Ding, Dong Liu, Shota Yajima, Kei Takahashi, Shuzi Hayase and Qing Shen
Nanomaterials 2023, 13(7), 1292; https://doi.org/10.3390/nano13071292 - 06 Apr 2023
Viewed by 1876
Abstract
Methylammonium lead iodide (MAPbI3) perovskite quantum dots (QDs) have become one of the most promising materials for optoelectronics. Understanding the dynamics of the charge transfer from MAPbI3 QDs to the charge transport layer (CTL) is critical for improving the performance [...] Read more.
Methylammonium lead iodide (MAPbI3) perovskite quantum dots (QDs) have become one of the most promising materials for optoelectronics. Understanding the dynamics of the charge transfer from MAPbI3 QDs to the charge transport layer (CTL) is critical for improving the performance of MAPbI3 QD photoelectronic devices. However, there is currently less consensus on this. In this study, we used an ultrafast transient absorption (TA) technique to investigate the dynamics of charge transfer from MAPbI3 QDs to CTL titanium dioxide (TiO2), elucidating the dependence of these kinetics on QD size with an injection rate from 1.6 × 1010 to 4.3 × 1010 s−1. A QD solar cell based on MAPbI3/TiO2 junctions with a high-power conversion efficiency (PCE) of 11.03% was fabricated, indicating its great potential for application in high-performance solar cells. Full article
(This article belongs to the Special Issue Semiconductor Nanomaterials for Optoelectronic Applications)
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15 pages, 2227 KiB  
Article
Antifouling Systems Based on a Polyhedral Oligomeric Silsesquioxane-Based Hexyl Imidazolium Salt Adsorbed on Copper Nanoparticles Supported on Titania
by Alessandro Presentato, Eleonora La Greca, Luca Consentino, Rosa Alduina, Leonarda Francesca Liotta and Michelangelo Gruttadauria
Nanomaterials 2023, 13(7), 1291; https://doi.org/10.3390/nano13071291 - 06 Apr 2023
Cited by 3 | Viewed by 1407
Abstract
The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances [...] Read more.
The reaction of octakis(3-chloropropyl)octasilsesquioxane with four equivalents of 1-hexylimidazole or 1-decylimidazole gave two products labelled as HQ-POSS (hexyl-imidazolium quaternized POSS) and DQ-POSS (decyl-imidazolium quaternized POSS) as regioisomer mixtures. An investigation of the biological activity of these two compounds revealed the higher antimicrobial performances of HQ-POSS against Gram-positive and Gram-negative microorganisms, proving its broad-spectrum activity. Due to its very viscous nature, HQ-POSS was adsorbed in variable amounts on the surface of biologically active oxides to gain advantages regarding the expendability of such formulations from an applicative perspective. Titania and 5 wt% Cu on titania were used as supports. The materials 10HQ-POSS/Ti and 15HQ-POSS/5CuTi strongly inhibited the ability of Pseudomonas PS27 cells—a bacterial strain described for its ability to handle very toxic organic solvents and perfluorinated compounds—to grow as planktonic cells. Moreover, the best formulations (i.e., 10HQ-POSS/Ti and 15HQ-POSS/5CuTi) could prevent Pseudomonas PS27 biofilm formation at a certain concentration (250 μg mL−1) which greatly impaired bacterial planktonic growth. Specifically, 15HQ-POSS/5CuTi completely impaired cell adhesion, thus successfully prejudicing biofilm formation and proving its suitability as a potential antifouling agent. Considering that most studies deal with quaternary ammonium salts (QASs) with long alkyl chains (>10 carbon atoms), the results reported here on hexylimidazolium-based POSS further deepen the knowledge of QAS formulations which can be used as antifouling compounds. Full article
(This article belongs to the Special Issue Feature Papers in Nanomaterials Science)
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9 pages, 1062 KiB  
Article
Amplifying the Output of a Triboelectric Nanogenerator Using an Intermediary Layer of Gallium-Based Liquid Metal Particles
by Jong Hyeok Kim, Ju-Hyung Kim and Soonmin Seo
Nanomaterials 2023, 13(7), 1290; https://doi.org/10.3390/nano13071290 - 06 Apr 2023
Cited by 3 | Viewed by 1377
Abstract
The production of energy has become a major issue in today’s world. Triboelectric nanogenerators (TENGs) are promising devices that can harvest mechanical energy and convert it into electrical energy. This study explored the use of Galinstan particles in the production of TENGs, which [...] Read more.
The production of energy has become a major issue in today’s world. Triboelectric nanogenerators (TENGs) are promising devices that can harvest mechanical energy and convert it into electrical energy. This study explored the use of Galinstan particles in the production of TENGs, which convert mechanical energy into electrical energy. During the curing process, the evaporation of the hexane solvent resulted in a film with varying concentrations of Galinstan particles. The addition of n-hexane during ultrasonication reduced the viscosity of the polydimethylsiloxane (PDMS) solution, allowing for the liquid metal (LM) particles to be physically pulverized into smaller pieces. The particle size distribution of the film with a Galinstan concentration of 23.08 wt.% was measured to be within a few micrometers through ultrasonic crushing. As the amount of LM particles in the PDMS film increased, the capacitance of the film also increased, with the LM/PDMS film with a 23.08% weight percentage exhibiting the highest capacitance value. TENGs were created using LM/PDMS films with different weight percentages and tested for open-circuit voltage, short-circuit current, and charge amount Q. The TENG with an LM/PDMS film with a 23.08% weight percentage had the highest relative permittivity, resulting in the greatest voltage, current, and charge amount. The use of Galinstan particles in PDMS films has potential applications in wearable devices, sensors, and biomedical fields. Full article
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15 pages, 4987 KiB  
Article
Piezoelectric Nanogenerators Fabricated Using Spin Coating of Poly(vinylidene fluoride) and ZnO Composite
by Md. Jahirul Islam, Hyeji Lee, Kihak Lee, Chanseob Cho and Bonghwan Kim
Nanomaterials 2023, 13(7), 1289; https://doi.org/10.3390/nano13071289 - 06 Apr 2023
Cited by 2 | Viewed by 1967
Abstract
In this context, the open-circuit voltage generated by either poly (vinylidene fluoride) or PVDF and ZnO composite sample before being enhanced to 4.2 V compared to 1.2 V for the samples of pure PVDF. The spin coating method was used to create a [...] Read more.
In this context, the open-circuit voltage generated by either poly (vinylidene fluoride) or PVDF and ZnO composite sample before being enhanced to 4.2 V compared to 1.2 V for the samples of pure PVDF. The spin coating method was used to create a composite film, which served as a piezoelectric nanogenerator (PNG). Zinc oxide (ZnO) nanoparticles and PVDF serve as the matrix for the coating structure. Thin films were created that employed the spin coating method to achieve the desired results of ZnO’s non-brittle outcome and piezoelectric characteristics, as well as PVDF for use in self-powered devices. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and fourier transform infrared (FT-IR) were used to evaluate the properties of these formations. The electrical properties of the film were measured using an oscilloscope. Results indicated that by adding ZnO nanoparticles to the PVDF samples, piezoelectric capabilities were enhanced compared to samples containing PVDF only. These results point to promising uses for various wearable devices, such as water strider robot systems and self-operating equipment. Full article
(This article belongs to the Section Energy and Catalysis)
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17 pages, 7498 KiB  
Article
Impact of Proton Irradiation on Medium Density Polyethylene/Carbon Nanocomposites for Space Shielding Applications
by Federica Zaccardi, Elisa Toto, Shreya Rastogi, Valeria La Saponara, Maria Gabriella Santonicola and Susanna Laurenzi
Nanomaterials 2023, 13(7), 1288; https://doi.org/10.3390/nano13071288 - 06 Apr 2023
Cited by 4 | Viewed by 1310
Abstract
The development of novel materials with improved radiation shielding capability is a fundamental step towards the optimization of passive radiation countermeasures. Polyethylene (PE) nanocomposites filled with carbon nanotubes (CNT) or graphene nanoplatelets (GNP) can be a good compromise for maintaining the radiation shielding [...] Read more.
The development of novel materials with improved radiation shielding capability is a fundamental step towards the optimization of passive radiation countermeasures. Polyethylene (PE) nanocomposites filled with carbon nanotubes (CNT) or graphene nanoplatelets (GNP) can be a good compromise for maintaining the radiation shielding properties of the hydrogen-rich polymer while endowing the material with multifunctional properties. In this work, nanocomposite materials based on medium-density polyethylene (MDPE) loaded with different amounts of multi-walled carbon nanotubes (MWCNT), GNPs, and hybrid MWCNT/GNP nanofillers were fabricated, and their properties were examined before and after proton exposure. The effects of irradiation were evaluated in terms of modifications in the chemical and physical structure, wettability, and surface morphology of the nanocomposites. The aim of this work was to define and compare the MDPE-based nanocomposite behavior under proton irradiation in order to establish the best system for applications as space shielding materials. Full article
(This article belongs to the Special Issue Nanomaterials for Potential Uses in Extraterrestrial Environments)
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19 pages, 10730 KiB  
Article
Enhanced Responsivity and Optoelectronic Properties of Self-Powered Solar-Blind Ag2O/β-Ga2O3 Heterojunction-Based Photodetector with Ag:AZO Co-Sputtered Electrode
by Younghwa Yoon, Sangbin Park, Taejun Park, Hyungmin Kim, Kyunghwan Kim and Jeongsoo Hong
Nanomaterials 2023, 13(7), 1287; https://doi.org/10.3390/nano13071287 - 06 Apr 2023
Cited by 1 | Viewed by 1302
Abstract
A Ag:AZO electrode was used as an electrode for a self-powered solar-blind ultraviolet photodetector based on a Ag2O/β-Ga2O3 heterojunction. The Ag:AZO electrode was fabricated by co-sputtering Ag and AZO heterogeneous targets using the structural characteristics of a Facing [...] Read more.
A Ag:AZO electrode was used as an electrode for a self-powered solar-blind ultraviolet photodetector based on a Ag2O/β-Ga2O3 heterojunction. The Ag:AZO electrode was fabricated by co-sputtering Ag and AZO heterogeneous targets using the structural characteristics of a Facing Targets Sputtering (FTS) system with two-facing targets, and the electrical, crystallographic, structural, and optical properties of the fabricated thin film were evaluated. A photodetector was fabricated and evaluated based on the research results that the surface roughness of the electrode can reduce the light energy loss by reducing the scattering and reflectance of incident light energy and improving the trapping phenomenon between interfaces. The thickness of the electrodes was varied from 20 nm to 50 nm depending on the sputtering time. The optoelectronic properties were measured under 254 nm UV-C light, the on/off ratio of the 20 nm Ag:AZO electrode with the lowest surface roughness was 2.01 × 108, and the responsivity and detectivity were 56 mA/W and 6.99 × 1011 Jones, respectively. The Ag2O/β-Ga2O3-based solar-blind photodetector with a newly fabricated top electrode exhibited improved response with self-powered characteristics. Full article
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15 pages, 3621 KiB  
Article
Development of Alkylthiazole-Based Novel Thermoelectric Conjugated Polymers for Facile Organic Doping
by Junho Kim, Eui Hyun Suh, Kyumin Lee, Gyuri Kim, Hansu Kim, Jaeyoung Jang and In Hwan Jung
Nanomaterials 2023, 13(7), 1286; https://doi.org/10.3390/nano13071286 - 06 Apr 2023
Viewed by 1617
Abstract
In this study, we developed two novel conjugated polymers that can easily be doped with F4TCNQ organic dopants using a sequential doping method and then studied their organic thermoelectric (OTE) properties. In particular, to promote the intermolecular ordering of OTE polymers in the [...] Read more.
In this study, we developed two novel conjugated polymers that can easily be doped with F4TCNQ organic dopants using a sequential doping method and then studied their organic thermoelectric (OTE) properties. In particular, to promote the intermolecular ordering of OTE polymers in the presence of the F4TCNQ dopant, alkylthiazole-based conjugated building blocks with highly planar backbone structures were synthesized and copolymerized. All polymers showed strong molecular ordering and edge-on orientation in the film state, even in the presence of the F4TCNQ organic dopant. Thus, the sequential doping process barely changed the molecular ordering of the polymer films while making efficient molecular doping. In addition, the doping efficiency was improved in the more π-extended polymer backbones with thienothiophene units due to the emptier space in the polymer lamellar structure to locate ionized F4TCNQ. Moreover, the study of organic thin-film transistors (OTFTs) revealed that higher hole mobility in OTFTs was the key to increasing the electrical conductivity of OTE devices fabricated using the sequential doping method. Full article
(This article belongs to the Special Issue Nanocomposites for Energy Harvesting)
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12 pages, 1707 KiB  
Article
Thymol-Nanoparticles as Effective Biocides against the Quarantine Pathogen Xylella fastidiosa
by Francesca Baldassarre, Daniele Schiavi, Serena Ciarroni, Vincenzo Tagliavento, Angelo De Stradis, Viviana Vergaro, Gian Paolo Suranna, Giorgio Mariano Balestra and Giuseppe Ciccarella
Nanomaterials 2023, 13(7), 1285; https://doi.org/10.3390/nano13071285 - 06 Apr 2023
Cited by 4 | Viewed by 1763
Abstract
Quarantine pathogens require the investigation of new tools for effective plant protection. In particular, research on sustainable agrochemicals is the actual challenge. Plant extracts, essential oils, and gels are natural sources of efficient biocides, such as aromatic secondary metabolites. Thymol is the major [...] Read more.
Quarantine pathogens require the investigation of new tools for effective plant protection. In particular, research on sustainable agrochemicals is the actual challenge. Plant extracts, essential oils, and gels are natural sources of efficient biocides, such as aromatic secondary metabolites. Thymol is the major phenolic constituent of thyme and oregano essential oils, and it can inhibit many pathogenic microbes. Thymol nanoparticles were obtained through adsorption on CaCO3 nanocrystals, exploiting their carrier action. High loading efficiency and capability were reached as verified through UV and TGA measurements. We report the first study of thymol effect on Xylella fastidiosa, conducing both fluorometric assay and in vitro inhibition assay. The first test confirmed the great antibacterial effect of this compound. Finally, an in vitro test revealed an interesting synergistic action of thymol and nanocarriers, suggesting the potential application of thymol-nanoparticles as effective biocides to control Xylella fastidiosa infection. Full article
(This article belongs to the Special Issue Innovation of Nanotechnology in Agriculture and Food Production)
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16 pages, 4687 KiB  
Article
Poly(lactic acid)/Plasticizer/Nano-Silica Ternary Systems: Properties Evolution and Effects on Degradation Rate
by Roberta Capuano, Roberto Avolio, Rachele Castaldo, Mariacristina Cocca, Giovanni Dal Poggetto, Gennaro Gentile and Maria Emanuela Errico
Nanomaterials 2023, 13(7), 1284; https://doi.org/10.3390/nano13071284 - 05 Apr 2023
Viewed by 1273
Abstract
Plasticized nanocomposites based on poly(lactic acid) have been prepared by melt mixing following a two-step approach, adding two different oligomeric esters of lactic acid (OLAs) as plasticizers and fumed silica nanoparticles. The nanocomposites maintained a remarkable elongation at break in the presence of [...] Read more.
Plasticized nanocomposites based on poly(lactic acid) have been prepared by melt mixing following a two-step approach, adding two different oligomeric esters of lactic acid (OLAs) as plasticizers and fumed silica nanoparticles. The nanocomposites maintained a remarkable elongation at break in the presence of the nanoparticles, with no strong effects on modulus and strength. Measuring thermo-mechanical properties as a function of aging time revealed a progressive deterioration of properties, with the buildup of phase separation, related to the nature of the plasticizer. Materials containing hydroxyl-terminated OLA showed a higher stability of properties upon aging. On the contrary, a synergistic effect of the acid-terminated plasticizer and silica nanoparticles was pointed out, inducing an accelerated hydrolytic degradation of PLA: materials at high silica content exhibited a marked brittleness and a dramatic decrease of molecular weight after 16 weeks of aging. Full article
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18 pages, 3896 KiB  
Article
Efficient mRNA Delivery with Lyophilized Human Serum Albumin-Based Nanobubbles
by Hiroshi Kida, Yutaro Yamasaki, Loreto B. Feril Jr., Hitomi Endo, Keiji Itaka and Katsuro Tachibana
Nanomaterials 2023, 13(7), 1283; https://doi.org/10.3390/nano13071283 - 05 Apr 2023
Cited by 2 | Viewed by 1943
Abstract
In this study, we developed an efficient mRNA delivery vehicle by optimizing a lyophilization method for preserving human serum albumin-based nanobubbles (HSA-NBs), bypassing the need for artificial stabilizers. The morphology of the lyophilized material was verified using scanning electron microscopy, and the concentration, [...] Read more.
In this study, we developed an efficient mRNA delivery vehicle by optimizing a lyophilization method for preserving human serum albumin-based nanobubbles (HSA-NBs), bypassing the need for artificial stabilizers. The morphology of the lyophilized material was verified using scanning electron microscopy, and the concentration, size, and mass of regenerated HSA-NBs were verified using flow cytometry, nanoparticle tracking analysis, and resonance mass measurements, and compared to those before lyophilization. The study also evaluated the response of HSA-NBs to 1 MHz ultrasound irradiation and their ultrasound (US) contrast effect. The functionality of the regenerated HSA-NBs was confirmed by an increased expression of intracellularly transferred Gluc mRNA, with increasing intensity of US irradiation. The results indicated that HSA-NBs retained their structural and functional integrity markedly, post-lyophilization. These findings support the potential of lyophilized HSA-NBs, as efficient imaging, and drug delivery systems for various medical applications. Full article
(This article belongs to the Special Issue Nanobubbles and Their Applications)
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11 pages, 2307 KiB  
Article
Research on the High Light Out-Coupling Efficiency Deep-Blue Top-Emitting Organic Light-Emitting Diode through FDTD Optical Simulation
by Saihu Pan, Suhao Hu and Bin Wei
Nanomaterials 2023, 13(7), 1282; https://doi.org/10.3390/nano13071282 - 05 Apr 2023
Viewed by 1483
Abstract
We have studied high light out-coupling efficiency top-emitting organic light-emitting diodes (TOLEDs) under the guidance of the finite-difference time-domain (FDTD) simulation. TOLED achieves an extraordinarily high light extraction efficiency at 468 nm, in deep-blue regions, of 49.70%, which is approximately 3.5 times that [...] Read more.
We have studied high light out-coupling efficiency top-emitting organic light-emitting diodes (TOLEDs) under the guidance of the finite-difference time-domain (FDTD) simulation. TOLED achieves an extraordinarily high light extraction efficiency at 468 nm, in deep-blue regions, of 49.70%, which is approximately 3.5 times that of the bottom light-emitting diode (BOLED) by changing the thickness of the organic layer and the position of the light-emitting layer in the FDTD simulation. Based on the simulation results, the TOLED with ultrahigh efficiency and narrow full width at half maximum is successfully fabricated, and the maximum external quantum efficiency of TOLED is almost 3.3 times that of the BOLED, which is perfectly consistent with the FDTD simulation results. Meanwhile, the shift of the electroluminescence spectrum of the TOLED is restricted within 10° in the angular-dependence test (0° to 80°). The optimized performance of the OLED indicates a new method to develop a high-performance device under the guidance of simulation. Full article
(This article belongs to the Special Issue Nanomaterial-Based Nano-Electronic and Photonic Devices)
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14 pages, 3592 KiB  
Article
Optoelectrical Properties of Hexamine Doped-Methylammonium Lead Iodide Perovskite under Different Grain-Shape Crystallinity
by Marjoni Imamora Ali Umar, Annisa Zahra Ahdaliza, Salah M. El-Bahy, Nur Aliza, Siti Naqiyah Sadikin, Jaenudin Ridwan, Abang Annuar Ehsan, Mohammed A. Amin, Zeinhom M. El-Bahy and Akrajas Ali Umar
Nanomaterials 2023, 13(7), 1281; https://doi.org/10.3390/nano13071281 - 05 Apr 2023
Cited by 5 | Viewed by 1210
Abstract
The crystallinity properties of perovskite influence their optoelectrical performance in solar cell applications. We optimized the grain shape and crystallinity of perovskite film by annealing treatment from 130 to 170 °C under high humidity (relative humidity of 70%). We found that the grain [...] Read more.
The crystallinity properties of perovskite influence their optoelectrical performance in solar cell applications. We optimized the grain shape and crystallinity of perovskite film by annealing treatment from 130 to 170 °C under high humidity (relative humidity of 70%). We found that the grain size, grain interface, and grain morphology of the perovskite are optimized when the sample was annealed at 150 °C for 1 h in the air. At this condition, the perovskite film is composed of 250 nm crystalline shape grain and compact inter-grain structure with an invincible grain interface. Perovskite solar cells device analysis indicated that the device fabricated using the samples annealed at 150 °C produced the highest power conversion efficiency, namely 17.77%. The open circuit voltage (Voc), short-circuit current density (Jsc), and fill factor (FF) of the device are as high as 1.05 V, 22.27 mA/cm2, and 0.76, respectively. Optoelectrical dynamic analysis using transient photoluminescence and electrochemical impedance spectroscopies reveals that (i) carrier lifetime in the champion device can be up to 25 ns, which is almost double the carrier lifetime of the sample annealed at 130 °C. (ii) The interfacial charge transfer resistance is low in the champion device, i.e., ~20 Ω, which has a crystalline grain morphology, enabling active photocurrent extraction. Perovskite’s behavior under annealing treatment in high humidity conditions can be a guide for the industrialization of perovskite solar cells. Full article
(This article belongs to the Special Issue Advanced Nanomaterials and Nanotechnology for Solar Cells)
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19 pages, 4766 KiB  
Article
Non-Noble FeCrOx Bimetallic Nanoparticles for Efficient NH3 Decomposition
by Meng Du, Lingling Guo, Hongju Ren, Xin Tao, Yunan Li, Bing Nan, Rui Si, Chongqi Chen and Lina Li
Nanomaterials 2023, 13(7), 1280; https://doi.org/10.3390/nano13071280 - 05 Apr 2023
Cited by 3 | Viewed by 1403
Abstract
Ammonia has the advantages of being easy to liquefy, easy to store, and having a high hydrogen content of 17.3 wt%, which can be produced without COx through an ammonia decomposition using an appropriate catalyst. In this paper, a series of FeCr [...] Read more.
Ammonia has the advantages of being easy to liquefy, easy to store, and having a high hydrogen content of 17.3 wt%, which can be produced without COx through an ammonia decomposition using an appropriate catalyst. In this paper, a series of FeCr bimetallic oxide nanocatalysts with a uniform morphology and regulated composition were synthesized by the urea two-step hydrolysis method, which exhibited the high-performance decomposition of ammonia. The effects of different FeCr metal ratios on the catalyst particle size, morphology, and crystal phase were investigated. The Fe0.75Cr0.25 sample exhibited the highest catalytic activity, with an ammonia conversion of nearly 100% at 650 °C. The dual metal catalysts clearly outperformed the single metal samples in terms of their catalytic performance. Besides XRD, XPS, and SEM being used as the means of the conventional characterization, the local structural changes of the FeCr metal oxide catalysts in the catalytic ammonia decomposition were investigated by XAFS. It was determined that the Fe metal and FeNx of the bcc structure were the active species of the ammonia-decomposing catalyst. The addition of Cr successfully prevented the Fe from sintering at high temperatures, which is more favorable for the formation of stable metal nitrides, promoting the continuous decomposition of ammonia and improving the decomposition activity of the ammonia. This work reveals the internal relationship between the phase and structural changes and their catalytic activity, identifies the active catalytic phase, thus guiding the design and synthesis of catalysts for ammonia decomposition, and excavates the application value of transition-metal-based nanocomposites in industrial catalysis. Full article
(This article belongs to the Special Issue Advanced Nanosheets for Carbon Neutrality and Electronic Devices)
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12 pages, 9947 KiB  
Article
Flexible Metamaterial Quarter-Wave Plate and Its Application in Blocking the Backward Reflection of Terahertz Waves
by Jinhai Sun, Yong-Qiang Liu, Jining Li, Xutao Zhang, He Cai, Xianli Zhu and Hongcheng Yin
Nanomaterials 2023, 13(7), 1279; https://doi.org/10.3390/nano13071279 - 05 Apr 2023
Cited by 3 | Viewed by 1378
Abstract
A terahertz flexible metamaterial quarter-wave plate (QWP) is designed and fabricated using polyimide as the substrate in this paper, with a 3 dB axial ratio bandwidth of 0.51 THz and high polarization conversion efficiency and transmittance. The effect of the incidence angle on [...] Read more.
A terahertz flexible metamaterial quarter-wave plate (QWP) is designed and fabricated using polyimide as the substrate in this paper, with a 3 dB axial ratio bandwidth of 0.51 THz and high polarization conversion efficiency and transmittance. The effect of the incidence angle on the polarization conversion performance of the QWP is discussed by measuring the transmissions at multiple incidence angles. The blocking effect of this QWP combined with a polarizer on the backward reflection of terahertz waves is investigated by terahertz time-domain spectral transmission experiments. By adjusting the angle of the QWP and polarizer with respect to the incident light in the optical path, a blocking efficiency of 20 dB can be achieved at a 20° incidence angle, with a bandwidth of 0.25 THz, a maximum blocking efficiency of 58 dB at 1.73 THz, and an insertion loss of only 1.4 dB. Flexible terahertz metamaterial QWPs and polarizers can effectively block harmful reflected waves in terahertz communication and other systems. They have the advantages of a simple structure, ultra-thinness and flexibility, easy integration, no external magnetic field, and no low-temperature and other environmental requirements, thus having broad application prospects for terahertz on-chip integrated systems. Full article
(This article belongs to the Special Issue Nanophotonics: Plasmons, Lasers and Photonic Crystals)
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11 pages, 2670 KiB  
Article
A Physical Model to Describe the Motion Behavior of BNNSs under Nanosecond Pulses
by Liang Zhao, Lin Zhou and Lin Yi Jin
Nanomaterials 2023, 13(7), 1278; https://doi.org/10.3390/nano13071278 - 04 Apr 2023
Viewed by 861
Abstract
This paper presents a physical model that provides a comprehensive understanding of the motion behavior of boron nitride nanosheets (BNNSs) immersed in ultrapure deionized water and subjected to a series of nanosecond pulses. In a study conducted by Y. Mi et al. The [...] Read more.
This paper presents a physical model that provides a comprehensive understanding of the motion behavior of boron nitride nanosheets (BNNSs) immersed in ultrapure deionized water and subjected to a series of nanosecond pulses. In a study conducted by Y. Mi et al. The authors explored the global alignment behavior of BNNSs and fitted the experimental data with an exponential decay function. However, this function lacks clear physical mechanisms and the significance of the fitting parameters remains unclear. To address this issue, we have developed a kinetic model that explicitly describes the underlying physical mechanisms. Furthermore, we propose a simplified mathematical model that not only predicts the displacement of BNNSs but also estimates the total time, velocity, and acceleration of the motion process. Full article
(This article belongs to the Special Issue Recent Advances in Two-Dimensional Monolayer Nanomaterials)
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15 pages, 3829 KiB  
Article
High-Speed Centrifugal Spinning Polymer Slip Mechanism and PEO/PVA Composite Fiber Preparation
by Peiyan Ye, Qinghua Guo, Zhiming Zhang and Qiao Xu
Nanomaterials 2023, 13(7), 1277; https://doi.org/10.3390/nano13071277 - 04 Apr 2023
Cited by 4 | Viewed by 1361
Abstract
Composite nanofibers with excellent physical and chemical properties are widely used in new energy, biomedical, environmental, electronic, and other fields. Their preparation methods have been investigated extensively by many experts. High-speed centrifugal spinning is a novel method used to fabricate composite nanofibers. The [...] Read more.
Composite nanofibers with excellent physical and chemical properties are widely used in new energy, biomedical, environmental, electronic, and other fields. Their preparation methods have been investigated extensively by many experts. High-speed centrifugal spinning is a novel method used to fabricate composite nanofibers. The slip mechanism of polymer solution flows is an important factor affecting the morphology and quality of composite nanofibers prepared by high-speed centrifugal spinning. As the polymer solution flows, the liquid wall slip occurs inside the nozzle, followed by liquid–liquid interface slip and gas–liquid interface slip. The factors affecting polymer slip were investigated by developing a mathematical model in the nozzle. This suggests that the magnitude of the velocity is an important factor that affects polymer slip and determines fiber quality and morphology. Under the same rotational speed, the smaller the nozzle diameter, the greater the concentration of velocity distribution and the smaller the diameter of the produced composite nanofibers. Finally, PEO/PVA composite nanofibers were prepared using high-speed centrifugal spinning equipment at 900–5000 rpm and nozzle diameters of 0.2 mm, 0.4 mm, 0.6 mm, and 0.8 mm. The morphology and quality of the collected PEO/PVA composite nanofibers were analyzed using scanning electron microscopy (SEM) and TG experiments. Then, the optimal parameters for the preparation of PEO/PVA composite nanofibers by high-speed centrifugal spinning were obtained by combining the external environmental factors in the preparation process. Theoretical evaluation and experimental data were provided for the centrifugal composite spinning slip mechanism and for the preparation of composite nanofibers. Full article
(This article belongs to the Special Issue Flexible Nanocomposite Films: Synthesis and Applications)
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9 pages, 4308 KiB  
Article
Structural and Optical Properties of Tungsten Disulfide Nanoscale Films Grown by Sulfurization from W and WO3
by Pangihutan Gultom, Jiang-Yan Chiang, Tzu-Tai Huang, Jung-Chuan Lee, Shu-Hsuan Su and Jung-Chung Andrew Huang
Nanomaterials 2023, 13(7), 1276; https://doi.org/10.3390/nano13071276 - 04 Apr 2023
Cited by 5 | Viewed by 2142
Abstract
Tungsten disulfide (WS2) was prepared from W metal and WO3 by ion beam sputtering and sulfurization in a different number of layers, including monolayer, bilayer, six-layer, and nine-layer. To obtain better crystallinity, the nine-layer of WS2 was also prepared [...] Read more.
Tungsten disulfide (WS2) was prepared from W metal and WO3 by ion beam sputtering and sulfurization in a different number of layers, including monolayer, bilayer, six-layer, and nine-layer. To obtain better crystallinity, the nine-layer of WS2 was also prepared from W metal and sulfurized in a furnace at different temperatures (800, 850, 900, and 950 °C). X-ray diffraction revealed that WS2 has a 2-H crystal structure and the crystallinity improved with increasing sulfurization temperature, while the crystallinity of WS2 sulfurized from WO3 (WS2-WO3) is better than that sulfurized from W-metal (WS2-W). Raman spectra show that the full-width at half maximum (FWHM) of WS2-WO3 is narrower than that of WS2-W. We demonstrate that high-quality monocrystalline WS2 thin films can be prepared at wafer scale by sulfurization of WO3. The photoluminescence of the WS2 monolayer is strongly enhanced and centered at 1.98 eV. The transmittance of the WS2 monolayer exceeds 80%, and the measured band gap is 1.9 eV, as shown by ultraviolet-visible-infrared spectroscopy. Full article
(This article belongs to the Special Issue Processing, Surfaces and Interfaces of Nanomaterials)
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17 pages, 4841 KiB  
Review
Enhancement Mechanism of Pt/Pd-Based Catalysts for Oxygen Reduction Reaction
by Xinqun Zhang, Jiaqi Wang and Yang Zhao
Nanomaterials 2023, 13(7), 1275; https://doi.org/10.3390/nano13071275 - 04 Apr 2023
Cited by 4 | Viewed by 1500
Abstract
The oxygen reduction reaction (ORR) is one of the key catalytic reactions for hydrogen fuel cells, biofuel cells and metal–air cells. However, due to the complex four-electron catalytic process, the kinetics of the oxygen reduction reaction are sluggish. Platinum group metal (PGM) catalysts [...] Read more.
The oxygen reduction reaction (ORR) is one of the key catalytic reactions for hydrogen fuel cells, biofuel cells and metal–air cells. However, due to the complex four-electron catalytic process, the kinetics of the oxygen reduction reaction are sluggish. Platinum group metal (PGM) catalysts represented by platinum and palladium are considered to be the most active ORR catalysts. However, the price and reserves of Pt/Pd are major concerns and issues for their commercial application. Improving the catalytic performance of PGM catalysts can effectively reduce their loading and material cost in a catalytic system, and they will be more economical and practical. In this review, we introduce the kinetics and mechanisms of Pt/Pd-based catalysts for the ORR, summarize the main factors affecting the catalytic performance of PGMs, and discuss the recent progress of Pt/Pd-based catalysts. In addition, the remaining challenges and future prospects in the design and improvement of Pt/Pd-based catalysts of the ORR are also discussed. Full article
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12 pages, 3643 KiB  
Article
In Vitro Evaluation of the Antifungal Effect of AgNPs on Fusarium oxysporum f. sp. lycopersici
by Karla Lizbeth Macías Sánchez, Hiram Deusdedut Rashid González Martínez, Raúl Carrera Cerritos and Juan Carlos Martínez Espinosa
Nanomaterials 2023, 13(7), 1274; https://doi.org/10.3390/nano13071274 - 04 Apr 2023
Cited by 2 | Viewed by 1529
Abstract
The application of nanomaterials in the agri-food industry can lead us to the formulation of new sustainable and effective pesticides for the control of fungi such as Fusarium oxysporum f. sp. lycopersici (Fol). This is a fungal plant pathogen for the tomato plant. [...] Read more.
The application of nanomaterials in the agri-food industry can lead us to the formulation of new sustainable and effective pesticides for the control of fungi such as Fusarium oxysporum f. sp. lycopersici (Fol). This is a fungal plant pathogen for the tomato plant. In this work, silver nanoparticles (AgNPs) were synthesized by a green methodology from Geranium leaf extract as a reducing agent. The poisoned food technique was used to determine the percentage of inhibition of Fol mycelial growth by the action of AgNPs. They were characterized by transmission electron microscopy (TEM, JEOL JEM-2100, Tokyo, Japan) and ultraviolet-visible spectroscopy (UV-VIS, DU 730 Beckman Coulter, Brea, CA, USA). Five different concentrations of AgNPs (10, 20, 40, 75, and 150 mg/L) were evaluated in vitro in order to determine the minimum inhibitory concentration (MIC) as well as the behavior of their antifungal activity in tomato fruit. Nanoparticles with spherical morphology and average diameters of 38.5 ± 18.5 nm were obtained. The maximum percentage of inhibition on the mycelial growth of Fol was 94.6 ± 0.1%, which was obtained using the AgNPs concentration of 150 mg/L and it was determined that the MIC corresponds to 75 mg/L. On the other hand, in a qualitative way, it was possible to observe an external inhibitory effect in the tomato fruit from the concentration of 10 mg/L. Finally, we can conclude that AgNPs are a viable alternative for alternative formulations applied in the agri-food industry as pesticide solutions. Full article
(This article belongs to the Special Issue Advanced Nanostructured Materials for Antimicrobial Applications)
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11 pages, 2362 KiB  
Communication
Temperature-Induced Irreversible Structural Transition in Fe1.1Mn1.9O4 Nanoparticles Synthesized by Combustion Method
by Aleksandr A. Spivakov, Chun-Rong Lin, Ying-Zhen Chen and Li-Huai Huang
Nanomaterials 2023, 13(7), 1273; https://doi.org/10.3390/nano13071273 - 04 Apr 2023
Viewed by 957
Abstract
Fe1.1Mn1.9O4 nanoparticles were successfully synthesized using a combustion method. The influence of the heating temperature on the evolution of the structural and magnetic properties has been studied using various methods. The structural analysis results revealed that as-synthesized nanoparticles [...] Read more.
Fe1.1Mn1.9O4 nanoparticles were successfully synthesized using a combustion method. The influence of the heating temperature on the evolution of the structural and magnetic properties has been studied using various methods. The structural analysis results revealed that as-synthesized nanoparticles have a tetragonal structure with an average size of ~24 nm. The magnetic measurements of the sample showed its ferrimagnetic nature at room temperature with hysteresis at low fields. Temperature-dependent magnetization measurements allowed for the conclusion that the Curie temperature for Fe1.1Mn1.9O4 nanoparticles was ~465 °C. After high-temperature magnetic measurements, during which the samples were heated to various maximum heating temperatures (Tmax.heat.) in the range from 500 to 900 °C, it was found that the structure of the samples after cooling to room temperature depended on the heating temperature. Herewith, when the heating temperature was 600 < Tmax.heat. < 700 °C, an irreversible structural phase transition occurred, and the cooled samples retained a high-temperature cubic structure. The results of the magnetic analysis showed that the samples, following high-temperature magnetic measurements, demonstrated ferrimagnetic behavior. Full article
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15 pages, 4312 KiB  
Article
Enhancement of Structural, Optical and Photoelectrochemical Properties of n−Cu2O Thin Films with K Ions Doping toward Biosensor and Solar Cell Applications
by Mahmoud Abdelfatah, Nourhan Darwesh, Mohamed A. Habib, Omar K. Alduaij, Abdelhamid El-Shaer and Walid Ismail
Nanomaterials 2023, 13(7), 1272; https://doi.org/10.3390/nano13071272 - 04 Apr 2023
Cited by 5 | Viewed by 1306
Abstract
n-type Cu2O thin films were grown on conductive FTO substrates using a low-cost electrodeposition method. The doping of the n−Cu2O thin films with K ions was well identified using XRD, Raman, SEM, EDX, UV-vis, PL, photocurrent, Mott–Schottky, and EIS [...] Read more.
n-type Cu2O thin films were grown on conductive FTO substrates using a low-cost electrodeposition method. The doping of the n−Cu2O thin films with K ions was well identified using XRD, Raman, SEM, EDX, UV-vis, PL, photocurrent, Mott–Schottky, and EIS measurements. The results of the XRD show the creation of cubic Cu2O polycrystalline and monoclinic CuO, with the crystallite sizes ranging from 55 to 25.2 nm. The Raman analysis confirmed the presence of functional groups corresponding to the Cu2O and CuO in the fabricated samples. Moreover, the samples’ crystallinity and morphology change with the doping concentrations which was confirmed by SEM. The PL results show two characteristic emission peaks at 520 and 690 nm which are due to the interband transitions in the Cu2O as well as the oxygen vacancies in the CuO, respectively. Moreover, the PL strength was quenched at higher doping concentrations which reveals that the dopant K limits e−/h+ pairs recombination by trapped electrons and holes. The optical results show that the absorption edge is positioned between 425 and 460 nm. The computed Eg for the undoped and K−doped n−Cu2O was observed to be between 2.39 and 2.21 eV. The photocurrent measurements displayed that the grown thin films have the characteristic behavior of n-type semiconductors. Furthermore, the photocurrent is enhanced by raising the doped concentration, where the maximum value was achieved with 0.1 M of K ions. The Mott–Schottky measurements revealed that the flat band potential and donor density vary with a doping concentration from −0.87 to −0.71 V and 1.3 × 1017 to 3.2 × 1017 cm−3, respectively. EIS shows that the lowest resistivity to charge transfer (Rct) was attained at a 0.1 M concentration of K ions. The outcomes indicate that doping n−Cu2O thin films are an excellent candidate for biosensor and photovoltaic applications. Full article
(This article belongs to the Special Issue Nanostructured Thin Films: From Synthesis to Application)
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14 pages, 2950 KiB  
Article
Nanocomposites of Silicon Oxides and Carbon: Its Study as Luminescent Nanomaterials
by Gabriel Omar Mendoza Conde, José Alberto Luna López, Zaira Jocelyn Hernández Simón, José Álvaro David Hernández de la Luz, Karim Monfil Leyva, Jesús Carrillo López, Haydee Patricia Martínez Hernández, Erick Gastellóu Hernández, Dainet Berman Mendoza and Javier Flores Méndez
Nanomaterials 2023, 13(7), 1271; https://doi.org/10.3390/nano13071271 - 04 Apr 2023
Viewed by 1384
Abstract
In this work, hybrid structures formed by nanostructured layers, which contain materials, such as porous silicon (PSi), carbon nanotubes (CNTs), graphene oxide (GO), and silicon-rich oxide (SRO), were studied. The PSi layers were obtained by electrochemical etching over which CNTs and GO were [...] Read more.
In this work, hybrid structures formed by nanostructured layers, which contain materials, such as porous silicon (PSi), carbon nanotubes (CNTs), graphene oxide (GO), and silicon-rich oxide (SRO), were studied. The PSi layers were obtained by electrochemical etching over which CNTs and GO were deposited by spin coating. In addition, SRO layers, in which silicon nanocrystals are embedded, were obtained by hot filament chemical vapor deposition (HFCVD) technique. Photoluminescence (PL) spectra were obtained from the hybrid structures with which a comparative analysis was completed among different PL ones. The SRO layers were used to confine the CNTs and GO. The main purpose of making these hybrid structures is to modulate their PL response and obtain different emission energy regions in the PL response. It was found that the PL spectra of the CNTs/SRO and GO/SRO structures exhibit a shift towards high energies compared to those obtained from the PSi layers; likewise, the PSi/CNTs/SRO and PSi/GO/SRO structures show a similar behavior. To identify the different emission mechanisms originated by PSi, GO, CNTs, and SRO, the PL spectra were deconvolved. It was found that the Psi/CNTs/SRO and Psi/GO/SRO structures exhibit a PL shift in respect to the PSi layers, for this reason, the modulation of the PL emission of the structures makes these hybrid structures promising candidates to be applied in the field of photonic and electroluminescent devices. Full article
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31 pages, 89637 KiB  
Review
Optical Processes behind Plasmonic Applications
by Viktoriia E. Babicheva
Nanomaterials 2023, 13(7), 1270; https://doi.org/10.3390/nano13071270 - 03 Apr 2023
Cited by 21 | Viewed by 3322
Abstract
Plasmonics is a revolutionary concept in nanophotonics that combines the properties of both photonics and electronics by confining light energy to a nanometer-scale oscillating field of free electrons, known as a surface plasmon. Generation, processing, routing, and amplification of optical signals at the [...] Read more.
Plasmonics is a revolutionary concept in nanophotonics that combines the properties of both photonics and electronics by confining light energy to a nanometer-scale oscillating field of free electrons, known as a surface plasmon. Generation, processing, routing, and amplification of optical signals at the nanoscale hold promise for optical communications, biophotonics, sensing, chemistry, and medical applications. Surface plasmons manifest themselves as confined oscillations, allowing for optical nanoantennas, ultra-compact optical detectors, state-of-the-art sensors, data storage, and energy harvesting designs. Surface plasmons facilitate both resonant characteristics of nanostructures and guiding and controlling light at the nanoscale. Plasmonics and metamaterials enable the advancement of many photonic designs with unparalleled capabilities, including subwavelength waveguides, optical nanoresonators, super- and hyper-lenses, and light concentrators. Alternative plasmonic materials have been developed to be incorporated in the nanostructures for low losses and controlled optical characteristics along with semiconductor-process compatibility. This review describes optical processes behind a range of plasmonic applications. It pays special attention to the topics of field enhancement and collective effects in nanostructures. The advances in these research topics are expected to transform the domain of nanoscale photonics, optical metamaterials, and their various applications. Full article
(This article belongs to the Special Issue Nanophotonics: Lasers, Gratings and Localized Surface Plasmons)
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13 pages, 9199 KiB  
Article
Luminescent Amorphous Silicon Oxynitride Systems: High Quantum Efficiencies in the Visible Range
by Pengzhan Zhang, Leng Zhang, Fei Lyu, Danbei Wang, Ling Zhang, Kongpin Wu, Sake Wang and Chunmei Tang
Nanomaterials 2023, 13(7), 1269; https://doi.org/10.3390/nano13071269 - 03 Apr 2023
Viewed by 1047
Abstract
In recent years, researchers have placed great importance on the use of silicon (Si)-related materials as efficient light sources for the purpose of realizing Si-based monolithic optoelectronic integration. Previous works were mostly focused on Si nanostructured materials, and, so far, exciting results from [...] Read more.
In recent years, researchers have placed great importance on the use of silicon (Si)-related materials as efficient light sources for the purpose of realizing Si-based monolithic optoelectronic integration. Previous works were mostly focused on Si nanostructured materials, and, so far, exciting results from Si-based compounds are still lacking. In this paper, we have systematically demonstrated the high photoluminescence external quantum efficiency (PL EQE) and internal quantum efficiency (PL IQE) of amorphous silicon oxynitride (a-SiNxOy) systems. Within an integration sphere, we directly measured the PL EQE values of a-SiNxOy, which ranged from approximately 2% to 10% in the visible range at room temperature. Then, we calculated the related PL IQE through temperature-dependent PL measurements. The obtained PL IQE values (~84% at 480 nm emission peak wavelength) were very high compared with those of reported Si-based luminescent thin films. We also calculated the temperature-dependent PL EQE values of a-SiNxOy systems, and discussed the related PL mechanisms. Full article
(This article belongs to the Special Issue Nanostructured Thin Films: From Synthesis to Application)
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11 pages, 5926 KiB  
Editorial
Advanced Carbon Nanostructures: Synthesis, Properties, and Applications
by Marianna V. Kharlamova, Christian Kramberger and Alexander I. Chernov
Nanomaterials 2023, 13(7), 1268; https://doi.org/10.3390/nano13071268 - 03 Apr 2023
Viewed by 1100
Abstract
Carbon nanomaterials are a class of materials that include allotropic modifications of carbon [...] Full article
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15 pages, 2939 KiB  
Article
One-Pot Synthesis of Silica-Coated Gold Nanostructures Loaded with Cyanine 5.5 for Cell Imaging by SERS Spectroscopy
by Aleksei N. Smirnov, Simar F. Aslanov, Denis V. Danilov, Olga Yu. Kurapova and Elena V. Solovyeva
Nanomaterials 2023, 13(7), 1267; https://doi.org/10.3390/nano13071267 - 03 Apr 2023
Cited by 3 | Viewed by 1761
Abstract
Anisotropic gold nanoparticles have been recognized as promising agents for medical diagnostics and cancer therapy due to their wide functionality, photothermal effect, and ability for optical signal amplification in the near-infrared range. In this work, a simple and rapid method for the preparation [...] Read more.
Anisotropic gold nanoparticles have been recognized as promising agents for medical diagnostics and cancer therapy due to their wide functionality, photothermal effect, and ability for optical signal amplification in the near-infrared range. In this work, a simple and rapid method for the preparation of bone-shaped gold nanoparticles coated with a dye-impregnated silica shell with an aminated surface is proposed. The possibility of further functionalization the nanostructures with a delivery vector using folic acid as an example is demonstrated. The average size of the resulting tags does not exceed 70 nm, meeting the criteria of cell endocytosis. The prepared tags exhibit surface-enhanced Raman scattering (SERS) spectra at excitation with lasers of 632.8 and 785 nm. Cell imaging is performed on HeLa cells based on the most pronounced SERS bands as a tracking signal. The obtained images, along with scanning electron microscopy of cell samples, revealed the tendency of tags to agglomerate during endocytosis followed by the “hot spots” effect. To evaluate the toxic and proliferative effect of the nanotags, an MTT assay was performed with two HeLa and HEP G2 cell lines. The results revealed higher viability for HEP G2 cells. Full article
(This article belongs to the Special Issue Advances in Nanoscale Materials in Biomedicine)
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15 pages, 8078 KiB  
Article
Thermal Fabrication of Magnetic Fe3O4 (Nanoparticle)@Carbon Sheets from Waste Resources for the Adsorption of Dyes: Kinetic, Equilibrium, and UV–Visible Spectroscopy Investigations
by Mohamed A. Habila, Mohamed S. Moshab, Ahmed Mohamed El-Toni, Zeid A. ALOthman and Ahmed Y. Badjah Hadj Ahmed
Nanomaterials 2023, 13(7), 1266; https://doi.org/10.3390/nano13071266 - 03 Apr 2023
Cited by 6 | Viewed by 1162
Abstract
Thermal treatment is applied for the direct conversion of palm stalk waste to Fe3O4 (np)@carbon sheets (Fe3O4 (np)@CSs). The effect of conversion temperature was investigated. The TEM examination of the prepared magnetic Fe3O4 (np)@CSs [...] Read more.
Thermal treatment is applied for the direct conversion of palm stalk waste to Fe3O4 (np)@carbon sheets (Fe3O4 (np)@CSs). The effect of conversion temperature was investigated. The TEM examination of the prepared magnetic Fe3O4 (np)@CSs showed the formation of Fe3O4 (np) in a matrix of carbon sheets as a coated layer with surface functional groups including carbonyl and hydroxyl groups. Removal of dyes such as methyl orange, methylene blue, and neutral red was achieved using fabricated Fe3O4 (np)@CSs which were prepared at 250 °C, 400 °C, and 700 °C in a weak acidic medium. By studying the contact time effect for the adsorption of methylene blue, neutral red, and methyl orange, using the fabricated Fe3O4 (np)@CSs which were prepared at 250 °C and 400 °C, equilibrium occurred between 120 min and 180 min. In addition, the first-order and second-order kinetic models were applied to the adsorption data. The results revealed that the adsorption data fit better with the second-order kinetic model. Furthermore, the Freundlich model was found to be more suitable for describing the process of the separation of the dyes onto Fe3O4 (np)@CSs which were prepared at 250 °C and 400 °C, suggesting heterogenous surfaces and multi-layer adsorption. Full article
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13 pages, 4383 KiB  
Article
Static and Dynamic Magnetic Properties of Fe3O4 Nanotubes
by Francisco Olea de la Hoz, Eduardo Saavedra, Alejandro Pereira and Juan Escrig
Nanomaterials 2023, 13(7), 1265; https://doi.org/10.3390/nano13071265 - 03 Apr 2023
Viewed by 1505
Abstract
In this paper, our objective was to investigate the static and dynamic magnetic properties of Fe3O4 nanotubes that are 1000 nm long, by varying the external radius and the thickness of the tube wall. We performed a detailed numerical analysis [...] Read more.
In this paper, our objective was to investigate the static and dynamic magnetic properties of Fe3O4 nanotubes that are 1000 nm long, by varying the external radius and the thickness of the tube wall. We performed a detailed numerical analysis by simulating hysteresis curves with an external magnetic field applied parallel to the axis of the tubes (along the z-axis). Our findings indicate that nanotubes with an external radius of 30 nm exhibit non-monotonic behavior in their coercivity due to a change in the magnetization reversal mechanism, which was not observed in nanotubes with external radii of 80 nm. Additionally, we explored the dynamic susceptibility of these nanotubes and found that the position and number of resonance peaks can be controlled by manipulating the nanotube geometry. Overall, our study provides valuable insights into the behavior of Fe3O4 nanotubes, which can aid in the design and improvement in pseudo-one-dimensional technological devices. Full article
(This article belongs to the Special Issue Growth, Characterization and Applications of Nanotubes: Volume II)
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