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Nanomaterials
Volume 14
Issue 19
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Nanomaterials, Volume 14, Issue 19 (October-1 2024) – 72 articles

Cover Story (view full-size image): This article reports the encapsulation of unpassivated Cs4PbBr6 ellipsoidal nanocrystals and pseudospherical quantum dots in silicon nanosheets and their enhanced photoluminescence, by taking advantage of the nanosheets for compatible integration with a traditional silicon semiconductor. Förster resonance energy transfer is observed due to the bandgap shifting with nanocrystal size. The efficiency of this transfer is imaged spatially, and the results show that the photoluminescence intensity increases five times over 30 min of UV excitation. Cs4PbBr6 quantum dots encapsulated in silicon nanosheets can lead to applications of halide perovskite light-emitting diodes. View this paper
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14 pages, 2879 KiB  
Article
Modulating Near-Infrared Persistent Luminescence via Diverse Preparation Approaches
by Xiaomeng Wang, Hengli Zhu, Yan Liu, Jingyuan Li, Lejia Cao, Jiaren Du and Hengwei Lin
Nanomaterials 2024, 14(19), 1613; https://doi.org/10.3390/nano14191613 - 9 Oct 2024
Viewed by 685
Abstract
Near-infrared (NIR) persistent luminescence (PersL) materials have attracted extensive attention due to their great promise in medical diagnostics, bio-imaging, night vision surveillance, multi-level anticounterfeiting, and information encryption. To achieve NIR PersL (micro/nano-) materials with the desired properties, a variety of synthesis methods have [...] Read more.
Near-infrared (NIR) persistent luminescence (PersL) materials have attracted extensive attention due to their great promise in medical diagnostics, bio-imaging, night vision surveillance, multi-level anticounterfeiting, and information encryption. To achieve NIR PersL (micro/nano-) materials with the desired properties, a variety of synthesis methods have been employed, including solid-phase reaction and liquid-phase synthesis. Different synthesis methods have different but important effects on the micro/nano-structure, luminescence, and PersL properties of the materials. Moreover, the influence of various synthesis methods on the properties of NIR PersL materials determines the selection of preparation approaches for other new material systems. Taking the representative NIR PersL ZnGa2O4:Cr3+ material as an example, four synthesis procedures are applied, namely, high-temperature solid-state reaction (SSR), high-temperature molten salt method (MSM), hydrothermal method (HM), and microwave-assisted solid-state (MASS) method. The structural and luminescent properties of samples made by SSR, MSM, HM, and MASS are compared. Notably, it is revealed that the MASS method can create additional trapping energy levels, which is of great significance for emerging applications. This work demonstrates the different effects of synthesis methods on PersL performance and provides a good guideline for the rapid and reasonable selection of preparation methods for diverse applications. Full article
(This article belongs to the Special Issue Facile Synthesis, Properties and Applications of Luminescent Nano-Phosphors)
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10 pages, 5838 KiB  
Article
The Influence of Etching Method on the Occurrence of Defect Levels in III-V and II-VI Materials
by Kinga Majkowycz, Krzysztof Murawski, Małgorzata Kopytko, Krzesimir Nowakowski-Szkudlarek, Marta Witkowska-Baran and Piotr Martyniuk
Nanomaterials 2024, 14(19), 1612; https://doi.org/10.3390/nano14191612 - 9 Oct 2024
Viewed by 754
Abstract
The influence of the etching method on the occurrence of defect levels in InAs/InAsSb type-II superlattice (T2SLs) and MCT photodiode is presented. For both analyzed detectors, the etching process was performed by two methods: wet chemical etching and dry etching using an ion [...] Read more.
The influence of the etching method on the occurrence of defect levels in InAs/InAsSb type-II superlattice (T2SLs) and MCT photodiode is presented. For both analyzed detectors, the etching process was performed by two methods: wet chemical etching and dry etching using an ion beam (RIE—reactive ion etching). The deep-level transient spectroscopy (DLTS) method was used to determine the defect levels occurring in the analyzed structures. The obtained results indicate that the choice of etching method affects the occurrence of additional defect levels in the MCT material, but it has no significance for InAs/InAsSb T2SLs. Full article
(This article belongs to the Special Issue Nanoelectronics: Materials, Devices and Applications (Second Edition))
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17 pages, 1738 KiB  
Article
Sustainable and Reusable Modified Membrane Based on Green Gold Nanoparticles for Efficient Methylene Blue Water Decontamination by a Photocatalytic Process
by Lucia Mergola, Luigi Carbone, Ermelinda Bloise, Maria Rosaria Lazzoi and Roberta Del Sole
Nanomaterials 2024, 14(19), 1611; https://doi.org/10.3390/nano14191611 - 8 Oct 2024
Viewed by 778
Abstract
Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and [...] Read more.
Methylene blue (MB) is a dye hazardous pollutant widely used in several industrial processes that represents a relevant source of water pollution. Thus, the research of new systems to avoid their environmental dispersion represents an important goal. In this work, an efficient and sustainable nanocomposite material based on green gold nanoparticles for MB water remediation was developed. Starting from the reducing and stabilizing properties of some compounds naturally present in Lambrusco winery waste (grape marc) extracts, green gold nanoparticles (GM-AuNPs) were synthesized and deposited on a supporting membrane to create an easy and stable system for water MB decontamination. GM-AuNPs, with a specific plasmonic band at 535 nm, and the modified membrane were first characterized by UV–vis spectroscopy, X-ray diffraction (XRD), and electron microscopy. Transmission electron microscopy analysis revealed the presence of two breeds of crystalline shapes, triangular platelets and round-shaped penta-twinned nanoparticles, respectively. The crystalline nature of GM-AuNPs was also confirmed from XRD analysis. The photocatalytic performance of the modified membrane was evaluated under natural sunlight radiation, obtaining a complete disappearance of MB (100%) in 116 min. The photocatalytic process was described from a pseudo-first-order kinetic with a rate constant (k) equal to 0.044 ± 0.010 min−1. The modified membrane demonstrated high stability since it was reused up to 20 cycles, without any treatment for 3 months, maintaining the same performance. The GM-AuNPs-based membrane was also tested with other water pollutants (methyl orange, 4-nitrophenol, and rhodamine B), revealing a high selectivity towards MB. Finally, the photocatalytic performance of GM-AuNPs-based membrane was also evaluated in real samples by using tap and pond water spiked with MB, obtaining a removal % of 99.6 ± 1.2% and 98.8 ± 1.9%, respectively. Full article
(This article belongs to the Special Issue Advanced Studies in Bionanomaterials)
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3 pages, 149 KiB  
Editorial
Nanomaterials and Nanotechnology for Energy Conversion and Storage
by Chuanyin Xiong and Qiusheng Zhou
Nanomaterials 2024, 14(19), 1610; https://doi.org/10.3390/nano14191610 - 8 Oct 2024
Viewed by 927
Abstract
The world is undergoing a new round of energy reform, and traditional fossil fuels have sparked people’s thinking due to their environmental and non-renewable issues [...] Full article
(This article belongs to the Special Issue Nanomaterials and Nanotechnology for Energy Conversion and Storage)
18 pages, 2671 KiB  
Article
Templating Iron(III) Oxides on DNA Molecules
by Siyaka Mj Zubairu, Sulaiman O. Idris, Casmir E. Gimba, Adamu Uzairu, Andrew Houlton and Benjamin R. Horrocks
Nanomaterials 2024, 14(19), 1609; https://doi.org/10.3390/nano14191609 - 7 Oct 2024
Viewed by 569
Abstract
Fe(III) oxides were prepared as free nanoparticles and on DNA templates via the precipitation of Fe(III) salts with NaOH in the presence/absence of DNA. Through control of the pH and temperature, FeOOH and Fe2O3 were synthesised. The formation of templated [...] Read more.
Fe(III) oxides were prepared as free nanoparticles and on DNA templates via the precipitation of Fe(III) salts with NaOH in the presence/absence of DNA. Through control of the pH and temperature, FeOOH and Fe2O3 were synthesised. The formation of templated materials FeOOH/DNA and Fe2O3/DNA was confirmed using UV-Vis absorption and FTIR spectra. The direct optical gap of Fe2O3/DNA was estimated as 3.2 eV; the absorption by FeOOH/DNA and Fe2O3/DNA at longer wavelengths is weaker, but consistent with indirect gaps near 2 eV. X-ray photoelectron spectra confirmed the presence of Fe(III) and DNA in the templated samples. Analysis of the X-ray diffraction patterns of both templated and non-templated FeOOH and Fe2O3 demonstrated that the materials were the α-FeOOH and α-Fe2O3 polymorphs with crystallite diameters of the DNA-templated materials estimated as 7.6 nm and 6.8 nm. Transmission electron microscopy showed needle-like crystals of both FeOOH and Fe2O3, but the Fe2O3 contains some globular structures. In contrast, the morphology of FeOOH/DNA and Fe2O3/DNA consists of needle-like crystallites of the respective oxides organised into complex dendritic structures with a length on the 10 μm scale formed by the DNA molecules. Finally, scanned conductance microscopy provided evidence for the conductivity of the FeOOH/DNA after alignment via molecular combing on an Si/SiO2 substrate. Fe2O3/DNA did not exhibit any detectable conductivity. Full article
(This article belongs to the Section Inorganic Materials and Metal-Organic Frameworks)
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16 pages, 3178 KiB  
Article
The Influence of Thickness and Spectral Properties of Green Color-Emitting Polymer Thin Films on Their Implementation in Wearable PLED Applications
by Kyparisis Papadopoulos, Despoina Tselekidou, Alexandros Zachariadis, Argiris Laskarakis, Stergios Logothetidis and Maria Gioti
Nanomaterials 2024, 14(19), 1608; https://doi.org/10.3390/nano14191608 - 7 Oct 2024
Viewed by 919
Abstract
A systematic investigation of optical, electrochemical, photophysical, and electrooptical properties of printable green color-emitting polymer (poly(9,9-dioctylfluorene-alt-bithiophene)) (F8T2) and spiro-copolymer (SPG-01T) was conducted to explore their potentiality as an emissive layer for wearable polymer light-emitting diode (PLED) applications. We compared the two photoactive polymers [...] Read more.
A systematic investigation of optical, electrochemical, photophysical, and electrooptical properties of printable green color-emitting polymer (poly(9,9-dioctylfluorene-alt-bithiophene)) (F8T2) and spiro-copolymer (SPG-01T) was conducted to explore their potentiality as an emissive layer for wearable polymer light-emitting diode (PLED) applications. We compared the two photoactive polymers in terms of their spectral characteristics and color purity, as these are the most critical factors for wearable lighting sources and optical sensors. Low-cost, solution-based methods and facile architecture were applied to produce rigid and flexible light-emitting devices with high luminance efficiencies. Emission bandwidths, color coordinates, operational characteristics, and luminance were also derived to evaluate the device’s stability. The tuning of emission’s spectral features by layer thickness variation was realized and was correlated with the interplay between H-aggregates and J-aggregates formations for both conjugated polymers. Finally, we applied the functional green light-emitting PLED devices based on the two studied materials for the detection of Rhodamine 6G. It was determined that the optical detection of the R6G photoluminescence is heavily influenced by the emission spectrum characteristics of the PLED and changes in the thickness of the active layer. Full article
(This article belongs to the Section Nanophotonics Materials and Devices)
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18 pages, 3292 KiB  
Article
Biosynthesis and Characterization of Iron Oxide Nanoparticles Using Chenopodium quinoa Extract
by Mercedes del Pilar Marcos-Carrillo, Noemi-Raquel Checca-Huaman, Edson C. Passamani and Juan A. Ramos-Guivar
Nanomaterials 2024, 14(19), 1607; https://doi.org/10.3390/nano14191607 - 5 Oct 2024
Viewed by 998
Abstract
In this study, we achieved the biosynthesis of novel 7–8 nm iron-oxide nanoparticles in the presence of different concentrations (5 to 50% w/v) of commercial white quinoa extract. Initially, quinoa extract was prepared at various concentrations by a purification route. [...] Read more.
In this study, we achieved the biosynthesis of novel 7–8 nm iron-oxide nanoparticles in the presence of different concentrations (5 to 50% w/v) of commercial white quinoa extract. Initially, quinoa extract was prepared at various concentrations by a purification route. The biosynthesis optimization was systematically monitored by X-ray diffraction, and the Rietveld quantitative analysis showed the presence of goethite (5 to 10 wt.%) and maghemite phases. The first phase disappeared upon increasing the organic loading (40 and 50% w/v). The organic loading was corroborated by thermogravimetric measurements, and it increased with quinoa extract concentration. Its use reduces the amount of precipitation agent at high quinoa extract concentrations with the formation of magnetic nanoparticles with hard ferrimagnetic character (42 and 11 emu g−1). The enrichment of hydroxyl groups and the negative zeta potential above pH = 7 were corroborated by a reduction in the point of zero charge in all the samples. For alkaline values, the zeta potential values were above the stability range, indicating highly stable chemical species. The evidence of hydroxyl and amide functionalization was qualitatively observed using infrared analysis, which showed that the carboxyl (quercetin/kaempferol), amide I, and amide III chemical groups are retained after biosynthesis. The resultant biosynthesized samples can find applications in environmental remediation due to the affinity of the chemical agents present on the particle surfaces and easy-to-handle them magnetically. Full article
(This article belongs to the Special Issue Biosynthesis and Green Synthesis of Nanomaterials: New Methodologies and Results, 2nd Edition)
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9 pages, 5581 KiB  
Article
ITO-Based Electrically Tunable Metasurface for Active Control of Light Transmission
by Ruize Ma, Yu Mao, Peiyang Li, Dong Li and Dandan Wen
Nanomaterials 2024, 14(19), 1606; https://doi.org/10.3390/nano14191606 - 5 Oct 2024
Viewed by 881
Abstract
In recent years, the rapid development of dynamically tunable metasurfaces has provided a new avenue for flexible control of optical properties. This paper introduces a transmission-type electrically tunable metasurface, employing a series of subwavelength-scale silicon (Si) nanoring structures with an intermediate layer of [...] Read more.
In recent years, the rapid development of dynamically tunable metasurfaces has provided a new avenue for flexible control of optical properties. This paper introduces a transmission-type electrically tunable metasurface, employing a series of subwavelength-scale silicon (Si) nanoring structures with an intermediate layer of Al2O3-ITO-Al2O3. This design allows the metasurface to induce strong Mie resonance when transverse electric (TE) waves are normally incident. When a bias voltage is applied, the interaction between light and matter is enhanced due to the formation of an electron accumulation layer at the ITO-Al2O3 interface, thereby altering the resonance characteristics of the metasurface. This design not only avoids the absorption loss of metal nanostructures and has a large modulation depth, but also shows compatibility with complementary metal oxide semiconductor (CMOS) technology. Full article
(This article belongs to the Special Issue Physical Properties of Semiconductor Nanostructures and Devices)
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13 pages, 7822 KiB  
Article
Optical Properties and Applications of Diffraction Grating Using Localized Surface Plasmon Resonance with Metal Nano-Hemispheres
by Tomoya Kubota, Shogo Tokimori, Kai Funato, Hiroaki Kawata, Tetsuya Matsuyama, Kenji Wada and Koichi Okamoto
Nanomaterials 2024, 14(19), 1605; https://doi.org/10.3390/nano14191605 - 5 Oct 2024
Viewed by 838
Abstract
This study investigates the optical properties of diffraction gratings using localized surface plasmon resonance (LSPR) with metal nano-hemispheres. We fabricated metal nano-hemisphere gratings (MNHGS) with Ga, Ag, and Au and examined their wavelength-selective diffraction properties. Our findings show that these gratings exhibit peak [...] Read more.
This study investigates the optical properties of diffraction gratings using localized surface plasmon resonance (LSPR) with metal nano-hemispheres. We fabricated metal nano-hemisphere gratings (MNHGS) with Ga, Ag, and Au and examined their wavelength-selective diffraction properties. Our findings show that these gratings exhibit peak diffraction efficiencies at 300 nm, 500 nm, and 570 nm, respectively, corresponding to the LSPR wavelengths of each metal. The MNHGs were created through thermal nanoimprint and metal deposition, followed by annealing. The experimental and simulation results confirmed that the MNHGs selectively diffract light at their resonance wavelengths. Applying these findings to third-order nonlinear laser spectroscopy (MPT-TG method) enhances measurement sensitivity by reducing background noise through the selective diffraction of pump light while transmitting probe light. This innovation promises a highly sensitive method for observing subtle optical phenomena, enhancing the capabilities of nonlinear laser spectroscopy. Full article
(This article belongs to the Special Issue Progress of Nanoscale Materials in Plasmonics and Photonics)
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31 pages, 6153 KiB  
Review
Sodium-Ion Battery at Low Temperature: Challenges and Strategies
by Yan Zhao, Zhen Zhang, Yalong Zheng, Yichao Luo, Xinyu Jiang, Yaru Wang, Zhoulu Wang, Yutong Wu, Yi Zhang, Xiang Liu and Baizeng Fang
Nanomaterials 2024, 14(19), 1604; https://doi.org/10.3390/nano14191604 - 4 Oct 2024
Viewed by 1090
Abstract
Sodium-ion batteries (SIBs) have garnered significant interest due to their potential as viable alternatives to conventional lithium-ion batteries (LIBs), particularly in environments where low-temperature (LT) performance is crucial. This paper provides a comprehensive review of current research on LT SIBs, focusing on electrode [...] Read more.
Sodium-ion batteries (SIBs) have garnered significant interest due to their potential as viable alternatives to conventional lithium-ion batteries (LIBs), particularly in environments where low-temperature (LT) performance is crucial. This paper provides a comprehensive review of current research on LT SIBs, focusing on electrode materials, electrolytes, and operational challenges specific to sub-zero conditions. Recent advancements in electrode materials, such as carbon-based materials and titanium-based materials, are discussed for their ability to enhance ion diffusion kinetics and overall battery performance at colder temperatures. The critical role of electrolyte formulation in maintaining battery efficiency and stability under extreme cold is highlighted, alongside strategies to mitigate capacity loss and cycle degradation. Future research directions underscore the need for further improvements in energy density and durability and scalable manufacturing processes to facilitate commercial adoption. Overall, LT SIBs represent a promising frontier in energy storage technology, with ongoing efforts aimed at overcoming technical barriers to enable widespread deployment in cold-climate applications and beyond. Full article
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13 pages, 8642 KiB  
Article
Analysis and Optimization of Light Absorption and Scattering Properties of Metal Nanocages
by Enhao Shao, Paerhatijiang Tuersun, Dilishati Wumaier, Shuyuan Li and Aibibula Abudula
Nanomaterials 2024, 14(19), 1603; https://doi.org/10.3390/nano14191603 - 4 Oct 2024
Viewed by 952
Abstract
Metal nanocages exhibit localized surface plasmon resonance that strongly absorbs and scatters light at specific wavelengths, making them potentially valuable for photothermal therapy and biological imaging applications. However, investigations on metal nanocages are still confined to high-cost and small-scale synthesis. The comprehensive analysis [...] Read more.
Metal nanocages exhibit localized surface plasmon resonance that strongly absorbs and scatters light at specific wavelengths, making them potentially valuable for photothermal therapy and biological imaging applications. However, investigations on metal nanocages are still confined to high-cost and small-scale synthesis. The comprehensive analysis of optical properties and optimal size parameters of metal nanocages is rarely reported. This paper simulates the effects of materials (Ag, Au, and Cu), size parameters, refractive index of the surrounding medium, and orientation on the light absorption and scattering characteristics of the nanocages using the finite-element method and the size-dependent refractive-index model for metal nanoparticles. The results show that the Ag nanocages have excellent light absorption and scattering characteristics and respond significantly to the size parameters, while the refractive index and orientation of the surrounding medium have less effect on them. The Au nanocages also possess superior light absorption properties at specific incident wavelengths. This study also identified the optimized sizes of three metal nanocages at incident light wavelengths commonly used in biomedicine; it was also found that, under deep therapy conditions, Ag nanocages in particular exhibit the highest volume absorption and scattering coefficients of 0.708 nm−1 and 0.583 nm−1, respectively. These findings offer theoretical insights into preparing target nanocage particles for applications in photothermal therapy and biological imaging. Full article
(This article belongs to the Special Issue Modeling, Simulation and Optimization of Nanomaterials)
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10 pages, 277 KiB  
Editorial
Advanced Porous Nanomaterials: Synthesis, Properties, and Applications
by Yannick Guari
Nanomaterials 2024, 14(19), 1602; https://doi.org/10.3390/nano14191602 - 3 Oct 2024
Viewed by 1290
Abstract
Porous nanomaterials have emerged as one of the most versatile and valuable classes of materials, captivating the attention of both scientists and engineers due to their exceptional functional and structural properties [...] Full article
(This article belongs to the Special Issue Advanced Porous Nanomaterials: Synthesis, Properties, and Application)
18 pages, 2442 KiB  
Article
Cytotoxic Potencies of Zinc Oxide Nanoforms in A549 and J774 Cells
by Nazila Nazemof, Dalibor Breznan, Yasmine Dirieh, Erica Blais, Linda J. Johnston, Azam F. Tayabali, James Gomes and Premkumari Kumarathasan
Nanomaterials 2024, 14(19), 1601; https://doi.org/10.3390/nano14191601 - 3 Oct 2024
Viewed by 1087
Abstract
Zinc oxide nanoparticles (NPs) are used in a wide range of consumer products and in biomedical applications, resulting in an increased production of these materials with potential for exposure, thus causing human health concerns. Although there are many reports on the size-related toxicity [...] Read more.
Zinc oxide nanoparticles (NPs) are used in a wide range of consumer products and in biomedical applications, resulting in an increased production of these materials with potential for exposure, thus causing human health concerns. Although there are many reports on the size-related toxicity of ZnO NPs, the toxicity of different nanoforms of this chemical, toxicity mechanisms, and potency determinants need clarification to support health risk characterization. A set of well-characterized ZnO nanoforms (e.g., uncoated ca. 30, 45, and 53 nm; coated with silicon oil, stearic acid, and (3-aminopropyl) triethoxysilane) were screened for in vitro cytotoxicity in two cell types, human lung epithelial cells (A549), and mouse monocyte/macrophage (J774) cells. ZnO (bulk) and ZnCl2 served as reference particles. Cytotoxicity was examined 24 h post-exposure by measuring CTB (viability), ATP (energy metabolism), and %LDH released (membrane integrity). Cellular oxidative stress (GSH-GSSG) and secreted proteins (targeted multiplex assay) were analyzed. Zinc oxide nanoform type-, dose-, and cell type-specific cytotoxic responses were seen, along with cellular oxidative stress. Cell-secreted protein profiles suggested ZnO NP exposure-related perturbations in signaling pathways relevant to inflammation/cell injury and corresponding biological processes, namely reactive oxygen species generation and apoptosis/necrosis, for some nanoforms, consistent with cellular oxidative stress and ATP status. The size, surface area, agglomeration state and metal contents of these ZnO nanoforms appeared to be physicochemical determinants of particle potencies. These findings warrant further research on high-content “OMICs” to validate and resolve toxicity pathways related to exposure to nanoforms to advance health risk-assessment efforts and to inform on safer materials. Full article
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3 pages, 147 KiB  
Editorial
Carbon-Based Multifunctional Nanomaterials
by Huitao Yu and Wei Feng
Nanomaterials 2024, 14(19), 1600; https://doi.org/10.3390/nano14191600 - 3 Oct 2024
Viewed by 569
Abstract
Carbon-based nanomaterials have garnered widespread attention and application because of their exceptional electrical conductivity, thermal conductivity, mechanical strength, and optical properties [...] Full article
(This article belongs to the Special Issue Carbon-Based Multifunctional Nanomaterials: Synthesis, Properties and Application)
14 pages, 2608 KiB  
Article
Structural and Optical Properties of Nickel-Doped Zinc Sulfide
by Sultan Alhassan, Alhulw H. Alshammari, Satam Alotibi, Khulaif Alshammari, W. S. Mohamed and N. M. A. Hadia
Nanomaterials 2024, 14(19), 1599; https://doi.org/10.3390/nano14191599 - 3 Oct 2024
Viewed by 823
Abstract
In this study, undoped and Ni-doped ZnS nanoparticles were fabricated using a hydrothermal method to explore their structural, optical, and surface properties. X-ray diffraction (XRD) analysis confirmed the cubic crystal structure of ZnS, with the successful incorporation of Ni ions at various doping [...] Read more.
In this study, undoped and Ni-doped ZnS nanoparticles were fabricated using a hydrothermal method to explore their structural, optical, and surface properties. X-ray diffraction (XRD) analysis confirmed the cubic crystal structure of ZnS, with the successful incorporation of Ni ions at various doping levels (2%, 4%, 6%, and 8%) without disrupting the overall lattice configuration. The average particle size for undoped ZnS was found to be 5.27 nm, while the Ni-doped samples exhibited sizes ranging from 5.45 nm to 5.83 nm, with the largest size observed at 6% Ni doping before a reduction at higher concentrations. Fourier-transform infrared (FTIR) spectroscopy identified characteristic Zn–S vibrational bands, with shifts indicating successful Ni incorporation into the ZnS lattice. UV–visible spectroscopy revealed a decrease in the optical band gap from 3.72 eV for undoped ZnS to 3.54 eV for 6% Ni-doped ZnS, demonstrating tunable optical properties due to Ni doping, which could enhance photocatalytic performance under visible light. Scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses confirmed the uniform distribution of Ni within the ZnS matrix, while X-ray photoelectron spectroscopy (XPS) provided further confirmation of the chemical states of the elements. Ni doping of ZnS nanoparticles alters the surface area and pore structure, optimizing the material’s textural properties for enhanced performance. These findings suggest that Ni-doped ZnS nanoparticles offer promising potential for applications in photocatalysis, optoelectronics, and other fields requiring specific band gap tuning and particle size control. Full article
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26 pages, 1757 KiB  
Review
Enhancing the Efficacy of Active Pharmaceutical Ingredients in Medicinal Plants through Nanoformulations: A Promising Field
by Yuhao Chen, Yuying Tang, Yuanbo Li, Yukui Rui and Peng Zhang
Nanomaterials 2024, 14(19), 1598; https://doi.org/10.3390/nano14191598 - 3 Oct 2024
Viewed by 1299
Abstract
This article explores the emerging field of nanomedicine as a drug delivery system, aimed at enhancing the therapeutic efficacy of active pharmaceutical ingredients in medicinal plants. The traditional methods of applying medicinal plants present several limitations, such as low bioavailability, poor solubility, challenges [...] Read more.
This article explores the emerging field of nanomedicine as a drug delivery system, aimed at enhancing the therapeutic efficacy of active pharmaceutical ingredients in medicinal plants. The traditional methods of applying medicinal plants present several limitations, such as low bioavailability, poor solubility, challenges in accurately controlling drug dosage, and inadequate targeting. Nanoformulations represent an innovative approach in drug preparation that employs nanotechnology to produce nanoscale particles or carriers, which are designed to overcome these limitations. Nanoformulations offer distinct advantages, significantly enhancing the solubility and bioavailability of drugs, particularly for the poorly soluble components of medicinal plants. These formulations effectively enhance solubility, thereby facilitating better absorption and utilization by the human body, which in turn improves drug efficacy. Furthermore, nanomedicine enables targeted drug delivery, ensuring precise administration to the lesion site and minimizing side effects on healthy tissues. Additionally, nanoformulations can regulate drug release rates, extend the duration of therapeutic action, and enhance the stability of treatment effects. However, nanoformulations present certain limitations and potential risks; their stability and safety require further investigation, particularly regarding the potential toxicity with long-term use. Nevertheless, nanomaterials demonstrate substantial potential in augmenting the efficacy of active pharmaceutical ingredients in medicinal plants, offering novel approaches and methodologies for their development and application. Full article
(This article belongs to the Section Environmental Nanoscience and Nanotechnology)
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12 pages, 7936 KiB  
Article
Controlled Fabrication of Wafer-Scale, Flexible Ag-TiO2 Nanoparticle–Film Hybrid Surface-Enhanced Raman Scattering Substrates for Sub-Micrometer Plastics Detection
by Fanyi Kong, Chenhua Ji, Gaolei Zhao, Lei Zhang, Zheng Hao, Hu Wang, Jianxun Dai, Huolin Huang, Lujun Pan and Dawei Li
Nanomaterials 2024, 14(19), 1597; https://doi.org/10.3390/nano14191597 - 3 Oct 2024
Viewed by 680
Abstract
As an important trace molecular detection technique, surface-enhanced Raman scattering (SERS) has been extensively investigated, while the realization of simple, low-cost, and controllable fabrication of wafer-scale, flexible SERS-active substrates remains challenging. Here, we report a facile, low-cost strategy for fabricating wafer-scale SERS substrates [...] Read more.
As an important trace molecular detection technique, surface-enhanced Raman scattering (SERS) has been extensively investigated, while the realization of simple, low-cost, and controllable fabrication of wafer-scale, flexible SERS-active substrates remains challenging. Here, we report a facile, low-cost strategy for fabricating wafer-scale SERS substrates based on Ag-TiO2 nanoparticle–film hybrids by combining dip-coating and UV light array photo-deposition. The results show that a centimeter-scale Ag nanoparticle (AgNP) film (~20 cm × 20 cm) could be uniformly photo-deposited on both non-flexible and flexible TiO2 substrates, with a relative standard deviation in particle size of only 5.63%. The large-scale AgNP/TiO2 hybrids working as SERS substrates show high sensitivity and good uniformity at both the micron and wafer levels, as evidenced by scanning electron microscopy and Raman measurements. In situ bending and tensile experiments demonstrate that the as-prepared flexible AgNP/TiO2 SERS substrate is mechanically robust, exhibiting stable SERS activity even in a large bending state as well as after more than 200 tensile cycles. Moreover, the flexible AgNP/TiO2 SERS substrates show excellent performance in detecting sub-micrometer-sized plastics (≤1 μm) and low-concentration organic pollutants on complex surfaces. Overall, this study provides a simple path toward wafer-scale, flexible SERS substrate fabrication, which is a big step for practical applications of the SERS technique. Full article
(This article belongs to the Special Issue Nonlinear Optics in Low-Dimensional Nanomaterials)
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13 pages, 4891 KiB  
Article
Förster Resonance Energy Transfer and Enhanced Emission in Cs4PbBr6 Nanocrystals Encapsulated in Silicon Nano-Sheets for Perovskite Light Emitting Diode Applications
by Araceli Herrera Mondragon, Roberto Gonzalez Rodriguez, Noah Hurley, Sinto Varghese, Yan Jiang, Brian Squires, Maoding Cheng, Brooke Davis, Qinglong Jiang, Mansour Mortazavi, Anupama B. Kaul, Jeffery L. Coffer, Jingbiao Cui and Yuankun Lin
Nanomaterials 2024, 14(19), 1596; https://doi.org/10.3390/nano14191596 - 3 Oct 2024
Viewed by 953
Abstract
Encapsulating Cs4PbBr6 quantum dots in silicon nano-sheets not only stabilizes the halide perovskite, but also takes advantage of the nano-sheet for a compatible integration with the traditional silicon semiconductor. Here, we report the preparation of un-passivated Cs4PbBr6 [...] Read more.
Encapsulating Cs4PbBr6 quantum dots in silicon nano-sheets not only stabilizes the halide perovskite, but also takes advantage of the nano-sheet for a compatible integration with the traditional silicon semiconductor. Here, we report the preparation of un-passivated Cs4PbBr6 ellipsoidal nanocrystals and pseudo-spherical quantum dots in silicon nano-sheets and their enhanced photoluminescence (PL). For a sample with low concentrations of quantum dots in silicon nano-sheets, the emission from Cs4PbBr6 pseudo-spherical quantum dots is quenched and is dominated with Pb2+ ion/silicene emission, which is very stable during the whole measurement period. For a high concentration of Cs4PbBr6 ellipsoidal nanocrystals in silicon nano-sheets, we have observed Förster resonance energy transfer with up to 87% efficiency through the oscillation of two PL peaks when UV excitation switches between on and off, using recorded video and PL lifetime measurements. In an area of a non-uniform sample containing both ellipsoidal nanocrystals and pseudo-spherical quantum dots, where Pb2+ ion/silicene emissions, broadband emissions from quantum dots, and bandgap edge emissions (515 nm) appear, the 515 nm peak intensity increases five times over 30 min of UV excitation, probably due to a photon recycling effect. This irradiated sample has been stable for one year of ambient storage. Cs4PbBr6 quantum dots encapsulated in silicon nano-sheets can lead to applications of halide perovskite light emitting diodes (PeLEDs) and integration with traditional semiconductor materials. Full article
(This article belongs to the Special Issue Nanostructured Materials for Electric Applications)
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13 pages, 3562 KiB  
Article
Efficient Formaldehyde Gas Sensing Performance via Promotion of Oxygen Vacancy on In-Doped LaFeO3 Nanofibers
by Lei Zhu, Jiaxin Zhang, Jianan Wang, Jianwei Liu, Wei Zhao and Wei Yan
Nanomaterials 2024, 14(19), 1595; https://doi.org/10.3390/nano14191595 - 2 Oct 2024
Viewed by 791
Abstract
Perovskite oxide LaFeO3(LFO) emerges as a potential candidate for formaldehyde (HCHO) detection due to its exceptional electrical conductivity and abundant active metal sites. However, the sensitivity of the LFO sensor needs to be further enhanced. Herein, a series of Lax [...] Read more.
Perovskite oxide LaFeO3(LFO) emerges as a potential candidate for formaldehyde (HCHO) detection due to its exceptional electrical conductivity and abundant active metal sites. However, the sensitivity of the LFO sensor needs to be further enhanced. Herein, a series of LaxIn1-xFeO3 (x = 1.0, 0.9, 0.8, and 0.7) nanofibers (LxIn1-xFO NFs) with different ratios of La/In were obtained via the electrospinning method followed by a calcination process. Among all these LxIn1-xFO NFs sensors, the sensor based on the L0.8In0.2FO NFs possessed the maximum response value of 18.8 to 100 ppm HCHO at the operating temperature of 180 °C, which was 4.47 times higher than that based on pristine LFO NFs (4.2). Furthermore, the L0.8In0.2FO NFs sensor also exhibited a rapid response/recovery time (2 s/22 s), exceptional repeatability, and long-term stability. This excellent gas sensing performance of the L0.8In0.2FO NFs can be attributed to the large number of oxygen vacancies induced by the replacement of the A-site La3+ by In3+, the large specific surface area, and the porous structure. This research presents an approach to enhance the HCHO gas sensing capabilities by adjusting the introduced oxygen vacancies through the doping of A-sites in perovskite oxides. Full article
(This article belongs to the Special Issue Nanoscale Material-Based Gas Sensors)
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14 pages, 2571 KiB  
Article
Magnetization States and Coupled Spin-Wave Modes in Concentric Double Nanorings
by Bushra Hussain and Michael G. Cottam
Nanomaterials 2024, 14(19), 1594; https://doi.org/10.3390/nano14191594 - 2 Oct 2024
Viewed by 798
Abstract
Concentric multiple nanorings have previously been fabricated and investigated mainly for their different static magnetization states. Here, we present a theoretical analysis for the magnetization dynamics in double nanorings arranged concentrically, where there is coupling across a nonmagnetic spacer due to the long-range [...] Read more.
Concentric multiple nanorings have previously been fabricated and investigated mainly for their different static magnetization states. Here, we present a theoretical analysis for the magnetization dynamics in double nanorings arranged concentrically, where there is coupling across a nonmagnetic spacer due to the long-range dipole–dipole interactions. We employ a microscopic, or Hamiltonian-based, formalism to study the discrete spin waves that exist in the magnetic states where the individual rings may be in either a vortex or an onion state. Numerical results are shown for the frequencies and the spatial amplitudes (with relative phase included) of the spin-wave modes. Cases are considered in which the magnetic materials of the rings are the same (taken to be permalloy) or two different materials such as permalloy and cobalt. The dependence of these properties on the mean radial position of the spacer were studied, showing, in most cases, the existence of two distinct transition fields. The special cases, where the radial spacer width becomes very small (less than 1 nm) were analyzed to study direct interfaces between dissimilar materials and/or effects of interfacial exchange interactions such as Ruderman–Kittel–Kasuya–Yoshida coupling. These spin-wave properties may be of importance for magnetic switching devices and sensors. Full article
(This article belongs to the Section Theory and Simulation of Nanostructures)
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8 pages, 1342 KiB  
Article
Metal-Cation-Induced Tiny Ripple on Graphene
by Yingying Huang, Hanlin Li, Liuyuan Zhu, Yongshun Song and Haiping Fang
Nanomaterials 2024, 14(19), 1593; https://doi.org/10.3390/nano14191593 - 2 Oct 2024
Viewed by 601
Abstract
Ripples on graphene play a crucial role in manipulating its physical and chemical properties. However, producing ripples, especially at the nanoscale, remains challenging with current experimental methods. In this study, we report that tiny ripples in graphene can be generated by the adsorption [...] Read more.
Ripples on graphene play a crucial role in manipulating its physical and chemical properties. However, producing ripples, especially at the nanoscale, remains challenging with current experimental methods. In this study, we report that tiny ripples in graphene can be generated by the adsorption of a single metal cation (Na+, K+, Mg2+, Ca2+, Cu2+, Fe3+) onto a graphene sheet, based on the density functional theory calculations. We attribute this to the cation–π interaction between the metal cation and the aromatic rings on the graphene surface, which makes the carbon atoms closer to metal ions, causing deformation of the graphene sheet, especially in the out-of-plane direction, thereby creating ripples. The equivalent pressures applied to graphene sheets in out-of-plane direction, generated by metal cation–π interactions, reach magnitudes on the order of gigapascals (GPa). More importantly, the electronic and mechanical properties of graphene sheets are modified by the adsorption of various metal cations, resulting in opened bandgaps and enhanced rigidity characterized by a higher elastic modulus. These findings show great potential for applications for producing ripples at the nanoscale in graphene through the regulation of metal cation adsorption. Full article
(This article belongs to the Section Synthesis, Interfaces and Nanostructures)
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16 pages, 2522 KiB  
Article
Electrochemical Detection of H2O2 Using Bi2O3/Bi2O2Se Nanocomposites
by Pooja D. Walimbe, Rajeev Kumar, Amit Kumar Shringi, Obed Keelson, Hazel Achieng Ouma and Fei Yan
Nanomaterials 2024, 14(19), 1592; https://doi.org/10.3390/nano14191592 - 2 Oct 2024
Viewed by 731
Abstract
The development of high-performance hydrogen peroxide (H2O2) sensors is critical for various applications, including environmental monitoring, industrial processes, and biomedical diagnostics. This study explores the development of efficient and selective H2O2 sensors based on bismuth oxide/bismuth [...] Read more.
The development of high-performance hydrogen peroxide (H2O2) sensors is critical for various applications, including environmental monitoring, industrial processes, and biomedical diagnostics. This study explores the development of efficient and selective H2O2 sensors based on bismuth oxide/bismuth oxyselenide (Bi2O3/Bi2O2Se) nanocomposites. The Bi2O3/Bi2O2Se nanocomposites were synthesized using a simple solution-processing method at room temperature, resulting in a unique heterostructure with remarkable electrochemical characteristics for H2O2 detection. Characterization techniques, including powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM), confirmed the successful formation of the nanocomposites and their structural integrity. The synthesis time was varied to obtain the composites with different Se contents. The end goal was to obtain phase pure Bi2O2Se. Electrochemical measurements revealed that the Bi2O3/Bi2O2Se composite formed under optimal synthesis conditions displayed high sensitivity (75.7 µA µM−1 cm−2) and excellent selectivity towards H2O2 detection, along with a wide linear detection range (0–15 µM). The superior performance is attributed to the synergistic effect between Bi2O3 and Bi2O2Se, enhancing electron transfer and creating more active sites for H2O2 oxidation. These findings suggest that Bi2O3/Bi2O2Se nanocomposites hold great potential as advanced H2O2 sensors for practical applications. Full article
(This article belongs to the Special Issue The Application of Nanoscale Materials in Batteries, Sensors and Supercapacitors (2nd Edition))
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8 pages, 2033 KiB  
Article
Synergic Effect of N and Se Facilitates Photoelectric Performance in Co-Hyperdoped Silicon
by Haibin Sun, Xiaolong Liu, Caixia Xu, Long Xu, Yuwei Chen, Haima Yang, Xing Yang, Peng Rao, Shengli Sun and Li Zhao
Nanomaterials 2024, 14(19), 1591; https://doi.org/10.3390/nano14191591 - 2 Oct 2024
Viewed by 645
Abstract
Femtosecond-laser-fabricated black silicon has been widely used in the fields of solar cells, photodetectors, semiconductor devices, optical coatings, and quantum computing. However, the responsive spectral range limits its application in the near- to mid-infrared wavelengths. To further increase the optical responsivity in longer [...] Read more.
Femtosecond-laser-fabricated black silicon has been widely used in the fields of solar cells, photodetectors, semiconductor devices, optical coatings, and quantum computing. However, the responsive spectral range limits its application in the near- to mid-infrared wavelengths. To further increase the optical responsivity in longer wavelengths, in this work, silicon (Si) was co-hyperdoped with nitrogen (N) and selenium (Se) through the deposition of Se films on Si followed by femtosecond (fs)-laser irradiation in an atmosphere of NF3. The optical and crystalline properties of the Si:N/Se were found to be influenced by the precursor Se film and laser fluence. The resulting photodetector, a product of this innovative approach, exhibited an impressive responsivity of 24.8 A/W at 840 nm and 19.8 A/W at 1060 nm, surpassing photodetectors made from Si:N, Si:S, and Si:S/Se (the latter two fabricated in SF6). These findings underscore the co-hyperdoping method’s potential in significantly improving optoelectronic device performance. Full article
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16 pages, 3691 KiB  
Article
Mixed Systems of Quaternary Ammonium Foam Drainage Agent with Carbon Quantum Dots and Silica Nanoparticles for Improved Gas Field Performance
by Yongqiang Sun, Yongping Zhang, Anqi Wei, Xin Shan, Qingwang Liu, Zhenzhong Fan, Ao Sun, Lin Zhu and Lingjin Kong
Nanomaterials 2024, 14(19), 1590; https://doi.org/10.3390/nano14191590 - 1 Oct 2024
Viewed by 802
Abstract
Foam drainage agents enhance gas production by removing wellbore liquids. However, due to the ultra-high salinity environments of the Hechuan gas field (salinity up to 32.5 × 104 mg/L), no foam drainage agent is suitable for this gas field. To address this [...] Read more.
Foam drainage agents enhance gas production by removing wellbore liquids. However, due to the ultra-high salinity environments of the Hechuan gas field (salinity up to 32.5 × 104 mg/L), no foam drainage agent is suitable for this gas field. To address this challenge, we developed a novel nanocomposite foam drainage system composed of quaternary ammonium and two types of nanoparticles. This work describes the design and synthesis of a quaternary ammonium foam drainage agent and nano-engineered stabilizers. Nonylphenol polyoxyethylene ether sulfosuccinate quaternary ammonium foam drainage agent was synthesized using maleic anhydride, sodium chloroacetate, N,N-dimethylpropylenediamine, etc., as precursors. We employed the Stöber method to create hydrophobic silica nanoparticles. Carbon quantum dots were then prepared and functionalized with dodecylamine. Finally, carbon quantum dots were incorporated into the mesopores of silica nanoparticles to enhance stability. Through optimization, the best performance was achieved with a (quaternary ammonium foam drainage agents)–(carbon quantum dots/silica nanoparticles) ratio of 5:1 and a total dosage of 1.1%. Under harsh conditions (salinity 35 × 104 mg/L, condensate oil 250 cm3/m3, temperature 80 °C), the system exhibited excellent stability with an initial foam height of 160 mm, remaining at 110 mm after 5 min. Additionally, it displayed good liquid-carrying capacity (160 mL), low surface tension (27.91 mN/m), and a long half-life (659 s). These results suggest the effectiveness of nanoparticle-enhanced foam drainage systems in overcoming high-salinity challenges. Previous foam drainage agents typically exhibited a salinity resistance of no more than 25 × 104 mg/L. In contrast, this innovative system demonstrates a superior salinity tolerance of up to 35 × 104 mg/L, addressing a significant gap in available agents for high-salinity gas fields. This paves the way for future development of advanced foam systems for gas well applications with high salinity. Full article
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16 pages, 6579 KiB  
Article
Thermo- and Photoresponsive Smart Nanomaterial Based on Poly(diethyl vinyl phosphonate)-Capped Gold Nanoparticles
by Antonio Buonerba, Rosita Lapenta, Francesco Della Monica, Roberto Piacentini, Lucia Baldino, Maria Rosa Scognamiglio, Vito Speranza, Stefano Milione, Carmine Capacchione, Bernhard Rieger and Alfonso Grassi
Nanomaterials 2024, 14(19), 1589; https://doi.org/10.3390/nano14191589 - 1 Oct 2024
Viewed by 759
Abstract
A new nanodevice based on gold nanoparticles (AuNPs) capped with poly(diethylvinylphosphonate) (PDEVP) has been synthesized, showing interesting photophysical and thermoresponsive properties. The synthesis involves a properly designed Yttriocene catalyst coordinating the vinyl-lutidine (VL) initiator active in diethyl vinyl phosphonate polymerization. The unsaturated PDEVP [...] Read more.
A new nanodevice based on gold nanoparticles (AuNPs) capped with poly(diethylvinylphosphonate) (PDEVP) has been synthesized, showing interesting photophysical and thermoresponsive properties. The synthesis involves a properly designed Yttriocene catalyst coordinating the vinyl-lutidine (VL) initiator active in diethyl vinyl phosphonate polymerization. The unsaturated PDEVP chain ending was thioacetylated, deacetylated, and reacted with tetrachloroauric acid and sodium borohydride to form PDEVP-VL-capped AuNPs. The NMR, UV–Vis, and ESI-MS characterization of the metal nanoparticles confirmed the formation of the synthetic intermediates and the expected colloidal systems. AuNPs of subnanometric size were determined by WAXD and UV–Vis analysis. UV–Vis and fluorescence analysis confirmed the effective anchoring of the thiolated PDEVP to AuNPs. The formation of 50–200 nm globular structures was assessed by SEM and AFM microscopy in solid state and confirmed by DLS in aqueous dispersion. Hydrodynamic radius studies showed colloidal contraction with temperature, demonstrating thermoresponsive behavior. These properties suggest potential biomedical applications for the photoablation of malignant cells or controlled drug delivery induced by light or heat for the novel PDEVP-capped AuNP systems. Full article
(This article belongs to the Special Issue Nanosomes in Precision Nanomedicine (Second Edition))
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26 pages, 8131 KiB  
Article
Renewable Resources as Promising Materials for Obtaining Graphene Oxide-like Structures
by Tilek Kuanyshbekov, Kydyrmolla Akatan, Nazim Guseinov, Renata Nemkaeva, Bayan Kurbanova, Zhandos Tolepov, Malika Tulegenova, Sana Kabdrakhmanova and Almira Zhilkashinova
Nanomaterials 2024, 14(19), 1588; https://doi.org/10.3390/nano14191588 - 1 Oct 2024
Viewed by 924
Abstract
Currently, one of the topical directions in the field of production and application of graphene-like nanostructures is the use of renewable natural raw materials, which have unlimited resources for an economically efficient large-scale yield of a product with environmental safety. In this regard, [...] Read more.
Currently, one of the topical directions in the field of production and application of graphene-like nanostructures is the use of renewable natural raw materials, which have unlimited resources for an economically efficient large-scale yield of a product with environmental safety. In this regard, we present the production of graphene oxide (GO) from a renewable natural raw material of plant biomass, birch activated carbon (BAC), and a comparison of the obtained physicochemical, mechanical, and electrical properties of birch activated carbon–graphene oxide (BAC–GO) and graphite–graphene oxide (G–GO) synthesized from the initial materials, BAC and graphite (G). Results obtained from this study confirm the successful oxidation of BAC, which correlates well with the physical–chemical dates of the G–GO and BAC–GO samples. Change in data after the oxidation of graphite and BAC was facilitated by the structure of the starting materials and, presumably, the location and content of functional oxygen-containing groups in the G–GO and BAC–GO chains. Based on the results, the application of a cost-effective, eco-friendly colloidal solution of nanodispersed BAC–GO from a plant biomass-based high-quality resource for producing large-scale nanostructured graphene is validated which has potential applicability in nanoelectronics, medicine, and other fields. Full article
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12 pages, 2650 KiB  
Article
Improvement of Electrical and Thermal Properties of Carbon Nanotube Sheets by Adding Silver Nanowire and Mxene for an Electromagnetic-Interference-Shielding Property Study
by Matthew Kurilich, Jin Gyu Park, Joshua Degraff, Qiang Wu and Richard Liang
Nanomaterials 2024, 14(19), 1587; https://doi.org/10.3390/nano14191587 - 1 Oct 2024
Viewed by 767
Abstract
Hybrid carbon nanotube (CNT) sheets were fabricated by mixing CNTs with silver nanowires (AgNWs) and MXene to study their electromagnetic-interference (EMI)-shielding properties. CNT/AgNW and CNT/MXene hybrid sheets were produced by ultrasonic homogenization and vacuum filtration, resulting in free-standing CNT sheets. Three different weight [...] Read more.
Hybrid carbon nanotube (CNT) sheets were fabricated by mixing CNTs with silver nanowires (AgNWs) and MXene to study their electromagnetic-interference (EMI)-shielding properties. CNT/AgNW and CNT/MXene hybrid sheets were produced by ultrasonic homogenization and vacuum filtration, resulting in free-standing CNT sheets. Three different weight ratios of AgNW and MXene were added to the CNT dispersions to produce hybrid CNT sheets. Microstructure characterization was performed using scanning electron microscopy, and the Wiedemann–Franz law was used to characterize transport properties. The resulting hybrid sheets exhibited improved electrical conductivity, thermal conductivity, and EMI-shielding effectiveness compared to pristine CNT sheets. X-band EMI-shielding effectiveness improved by over 200%, while electrical conductivity improved by more than 1500% in the hybrid sheets due to a higher charge-carrier density and synergistic effects between nanomaterials. The addition of AgNW to CNT sheets resulted in a large improvement in electrical conductivity and EMI shielding; however, this may also result in increased weight and sample thickness. Similarly, the addition of MXene to CNT sheets may result in an increase in weight due to the presence of the denser MXene flakes. Full article
(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)
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27 pages, 4919 KiB  
Article
Features of High-Precision Photothermal Analysis of Liquid Systems by Dual-Beam Thermal Lens Spectrometry
by Vladislav R. Khabibullin, Ivan V. Mikheev and Mikhail A. Proskurnin
Nanomaterials 2024, 14(19), 1586; https://doi.org/10.3390/nano14191586 - 1 Oct 2024
Viewed by 665
Abstract
Thermal lens spectrometry is a high-sensitivity method for measuring the optical and thermal parameters of samples of different nature. To obtain both thermal diffusivity and absorbance-based signal measurements with high accuracy and precision, it is necessary to pay attention to the factors that [...] Read more.
Thermal lens spectrometry is a high-sensitivity method for measuring the optical and thermal parameters of samples of different nature. To obtain both thermal diffusivity and absorbance-based signal measurements with high accuracy and precision, it is necessary to pay attention to the factors that influence the trueness of photothermal measurements. In this study, the features of liquid objects are studied, and the influence of optical and thermal effects accompanying photothermal phenomena are investigated. Thermal lens analysis of dispersed solutions and systems with photoinduced activity is associated with a large number of side effects, the impact of which on trueness is not always possible to determine. It is necessary to take into account the physicochemical properties and optical and morphological features of the nanophase and components exhibiting photoinduced activity. The results obtained make it possible to reduce systematic and random errors in determining the thermal-diffusivity-based and absorbance-based photothermal signals for liquid objects, and also contribute to a deeper understanding of the physicochemical processes in the sample. Full article
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13 pages, 896 KiB  
Article
Characteristic Times for Gap Relaxation and Heat Escape in Nanothin NbTi Superconducting Filaments: Thickness Dependence and Effect of Substrate
by Khalil Harrabi, Abdelkrim Mekki and Milorad V. Milošević
Nanomaterials 2024, 14(19), 1585; https://doi.org/10.3390/nano14191585 - 30 Sep 2024
Viewed by 641
Abstract
We measured the temporal voltage response of NbTi superconducting filaments with varied nanoscale thicknesses to step current pulses that induce non-equilibrium superconducting states governed by a hot spot mechanism. Such detected voltage emerges after a delay time td, which is intimately [...] Read more.
We measured the temporal voltage response of NbTi superconducting filaments with varied nanoscale thicknesses to step current pulses that induce non-equilibrium superconducting states governed by a hot spot mechanism. Such detected voltage emerges after a delay time td, which is intimately connected to the gap relaxation and heat escape times. By employing time-dependent Ginzburg–Landau theory to link the delay time to the applied current, we determined that the gap relaxation time depends linearly on film thickness, aligning with the acoustic mismatch theory for phonon transmission at the superconductor–substrate interface. We thereby find a gap relaxation time of 104 ps per nm of thickness for NbTi films on polished sapphire. We further show that interfacial interaction with the substrate significantly impacts the gap relaxation time, with observed values of 9 ns on SiOx, 6.8 ns on fused silica, and 5.2 ns on sapphire for a 50 nm thick NbTi strip at T=5.75 K. These insights are valuable for optimizing superconducting sensing technologies, particularly the single-photon detectors that operate in the transient regime of nanothin superconducting bridges and filaments. Full article
(This article belongs to the Section Nanoelectronics, Nanosensors and Devices)
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13 pages, 3754 KiB  
Article
Size Effects of Copper(I) Oxide Nanospheres on Their Morphology on Copper Thin Films under Near-Infrared Femtosecond Laser Irradiation
by Mizue Mizoshiri, Thuan Duc Tran and Kien Vu Trung Nguyen
Nanomaterials 2024, 14(19), 1584; https://doi.org/10.3390/nano14191584 - 30 Sep 2024
Viewed by 705
Abstract
The femtosecond laser direct writing of metals has gained significant attention for micro/nanostructuring. Copper (I) oxide nanospheres (NSs), a promising material for multi-photon metallization, can be reduced to copper (Cu) and sintered through near-infrared femtosecond laser pulse irradiation. In this study, we investigated [...] Read more.
The femtosecond laser direct writing of metals has gained significant attention for micro/nanostructuring. Copper (I) oxide nanospheres (NSs), a promising material for multi-photon metallization, can be reduced to copper (Cu) and sintered through near-infrared femtosecond laser pulse irradiation. In this study, we investigated the size effect of copper (I) oxide nanospheres on their morphology when coated on Cu thin films and irradiated by near-infrared femtosecond laser pulses. Three Cu2O NS inks were prepared, consisting of small (φ100 nm), large (φ200 nm), and a mixture of φ100 nm and φ200 nm NSs. A unique phenomenon was observed at low laser pulse energy: both sizes of NSs bonded as single layers when the mixed NSs were used. At higher pulse energies, the small NSs melted readily compared to the large NSs. In comparisons between the large and mixed NSs, some large NSs remained intact, suggesting that the morphology of the NSs can be controlled by varying the concentration of different-sized NSs. Considering the simulation results indicating that the electromagnetic fields between large and small NSs are nearly identical, this differential morphology is likely attributed to the differences in the heat capacity of the NSs. Full article
(This article belongs to the Special Issue Laser-Based Nano Fabrication and Nano Lithography: Second Edition)
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