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Nanomaterials, Volume 13, Issue 1 (January-1 2023) – 219 articles

Cover Story (view full-size image): Metasurfaces with a high engineering degree of freedom are promising building blocks for applications in light field modulations. Here, tunable metasurfaces with monolithic dielectric materials are introduced and investigated in detail. Changes in the period number and surrounding refractive index enable discrete and continuous modulations of spatial light fields, respectively. The utilization of monolithic dielectric materials facilitates the ready integration of metasurfaces with both chip and optical fiber platforms for beam focusing and deflection. This concept is not limited by the availability of active materials or expensive and time-consuming fabrication techniques, increasing the application opportunity of tunable metasurfaces. View this paper
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11 pages, 2919 KiB  
Article
Multi-Mode Lanthanide-Doped Ratiometric Luminescent Nanothermometer for Near-Infrared Imaging within Biological Windows
by Hao Li, Esmaeil Heydari, Yinyan Li, Hui Xu, Shiqing Xu, Liang Chen and Gongxun Bai
Nanomaterials 2023, 13(1), 219; https://doi.org/10.3390/nano13010219 - 3 Jan 2023
Cited by 6 | Viewed by 2382
Abstract
Owing to its high reliability and accuracy, the ratiometric luminescent thermometer can provide non-contact and fast temperature measurements. In particular, the nanomaterials doped with lanthanide ions can achieve multi-mode luminescence and temperature measurement by modifying the type of doped ions and excitation light [...] Read more.
Owing to its high reliability and accuracy, the ratiometric luminescent thermometer can provide non-contact and fast temperature measurements. In particular, the nanomaterials doped with lanthanide ions can achieve multi-mode luminescence and temperature measurement by modifying the type of doped ions and excitation light source. The better penetration of the near-infrared (NIR) photons can assist bio-imaging and replace thermal vision cameras for photothermal imaging. In this work, we prepared core–shell cubic phase nanomaterials doped with lanthanide ions, with Ba2LuF7 doped with Er3+/Yb3+/Nd3+ as the core and Ba2LaF7 as the coating shell. The nanoparticles were designed according to the passivation layer to reduce the surface energy loss and enhance the emission intensity. Green upconversion luminescence can be observed under both 980 nm and 808 nm excitation. A single and strong emission band can be obtained under 980 nm excitation, while abundant and weak emission bands appear under 808 nm excitation. Meanwhile, multi-mode ratiometric optical thermometers were achieved by selecting different emission peaks in the NIR window under 808 nm excitation for non-contact temperature measurement at different tissue depths. The results suggest that our core–shell NIR nanoparticles can be used to assist bio-imaging and record temperature for biomedicine. Full article
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14 pages, 2411 KiB  
Article
Evaporative and Wicking Functionalities at Hot Airflows of Laser Nano-/Microstructured Ti-6Al-4V Material
by Ranran Fang, Zhonglin Pan, Jiangen Zheng, Xiaofa Wang, Rui Li, Chen Yang, Lianrui Deng and Anatoliy Y. Vorobyev
Nanomaterials 2023, 13(1), 218; https://doi.org/10.3390/nano13010218 - 3 Jan 2023
Cited by 3 | Viewed by 1778
Abstract
A novel multifunctional material with efficient wicking and evaporative functionalities was fabricated using hierarchical surface nano-/microstructuring by femtosecond laser micromachining. The created material exhibits excellent multifunctional performance. Our experiments in a wind tunnel demonstrate its good wicking and evaporative functionalities under the conditions [...] Read more.
A novel multifunctional material with efficient wicking and evaporative functionalities was fabricated using hierarchical surface nano-/microstructuring by femtosecond laser micromachining. The created material exhibits excellent multifunctional performance. Our experiments in a wind tunnel demonstrate its good wicking and evaporative functionalities under the conditions of high-temperature airflows. An important finding of this work is the significantly enhanced evaporation rate of the created material compared with the free water surface. The obtained results provide a platform for the practical implementation of Maisotsenko-cycle cooling technologies for substantially increasing efficiency in power generation, thermal management, and other evaporation-based technologies. The developed multifunctional material demonstrates long-lasting wicking and evaporative functionalities that are resistant to degradation under high-temperature airflows, indicating its suitability for practical applications. Full article
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2 pages, 180 KiB  
Editorial
Thermophysical Properties of Nanocolloids and Their Potential Applications
by Alina Adriana Minea
Nanomaterials 2023, 13(1), 217; https://doi.org/10.3390/nano13010217 - 3 Jan 2023
Viewed by 1144
Abstract
This Special Issue is a continuation of the previous successful Special Issue, entitled “Future and Prospects in Nanofluids Research”, co-edited by the present Editor and dedicated to the topic of “Thermophysical Properties of Nanocolloids and Their Potential Applications” [...] Full article
14 pages, 4491 KiB  
Article
Improvement of Carbonyl Groups and Surface Defects in Carbon Nanotubes to Activate Peroxydisulfate for Tetracycline Degradation
by Wenxi Wang, Junjie Zhang, Zhiran Hou, Pei Chen, Xu Zhou, Wei Wang, Fatang Tan, Xinyun Wang and Xueliang Qiao
Nanomaterials 2023, 13(1), 216; https://doi.org/10.3390/nano13010216 - 3 Jan 2023
Cited by 6 | Viewed by 1752
Abstract
Carbon nanotubes (CNTs) were considered a promising activator for persulfates due to their high electrical conductivity, large specific surface area and low toxicity. The functional groups and surface defects of CNTs could significantly affect their activation performance. In this study, CNTs with high [...] Read more.
Carbon nanotubes (CNTs) were considered a promising activator for persulfates due to their high electrical conductivity, large specific surface area and low toxicity. The functional groups and surface defects of CNTs could significantly affect their activation performance. In this study, CNTs with high C=O ratio and defect density (CNT-O-H) were prepared through a facile treatment of raw CNTs with HNO3 oxidation followed by calcination at 800 °C under an argon atmosphere. X-ray photoelectron spectroscopy (XPS) and Raman results showed that the C=O proportion and defect degree (ID/IG) rose to 75% and 1.53, respectively. The obtained CNT-O-H possessed a superior performance towards peroxydisulfate (PDS) activation, and the degradation efficiency of tetracycline (TC) in the CNT-O-H/PDS system was increased to 75.2% from 56.2% of the raw CNTs/PDS system within 40 min. Moreover, the activity of CNT-O-H after use could be easily recovered with re-calcination. In addition, the CNT-O-H/PDS system exhibited high adaptabilities towards wide solution pH (2–10), common coexisting substances and diverse organic pollutants. Singlet oxygen (1O2) was confirmed to be the dominant reactive oxygen species (ROS) generated in the CNT-O-H/PDS system. It was inferred that surface C=O groups and defects of CNTs were the key site to activate PDS for TC degradation. Full article
(This article belongs to the Special Issue Nanomaterials for Detection and Removal of Organic Pollutants)
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12 pages, 5679 KiB  
Article
AZO Nanoparticles-Decorated CNTs for UV Light Sensing: A Structural, Chemical, and Electro-Optical Investigation
by Simona Filice, Stefano Boscarino, Mario Scuderi, Sebania Libertino, Clelia Galati, Antonio Terrasi and Silvia Scalese
Nanomaterials 2023, 13(1), 215; https://doi.org/10.3390/nano13010215 - 3 Jan 2023
Cited by 1 | Viewed by 1577
Abstract
Nanocomposites formed by aluminum-doped zinc oxide nanoparticles (AZO–NP) and multiwall carbon nanotubes (CNT) are proposed here as a promising material for UV light sensing applications, with the great advantage of operating in air, at room temperature, and at low voltage. Nanocomposite layers were [...] Read more.
Nanocomposites formed by aluminum-doped zinc oxide nanoparticles (AZO–NP) and multiwall carbon nanotubes (CNT) are proposed here as a promising material for UV light sensing applications, with the great advantage of operating in air, at room temperature, and at low voltage. Nanocomposite layers were prepared with different AZO:CNT weight ratios by a simple methodology at room temperature. They were characterized by means of UV–Vis spectroscopy, scanning and transmission electron microscopies (SEM and TEM), and X-ray photoelectron spectroscopy (XPS). The interaction between the two nanomaterials was demonstrated by comparing the properties of the nanocomposite with the ones shown by the AZO–NPs. Dense AZO–CNT nanocomposite layers were deposited between two metal electrodes on a SiO2/Si substrate, and the electrical properties were investigated in dark condition and under UV light irradiation. The electrical response to the UV light was a sudden current increase that reduced when the light was switched off. Several UV on/off cycles were performed, showing good repeatability and stability of the response. The mechanisms involved in the electrical response are discussed and compared to the ones previously reported for ZnO–CNT nanocomposites. Full article
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17 pages, 5612 KiB  
Article
Construction and Enhanced Efficiency of Bi2MoO6/ZnO Compo-Sites for Visible-Light-Driven Photocatalytic Performance
by Liyun Yan, Jiahui Tang, Qing-an Qiao, Honglan Cai, Yuqi Dong, Juan Jin, Yanbin Xu and Hongwei Gao
Nanomaterials 2023, 13(1), 214; https://doi.org/10.3390/nano13010214 - 3 Jan 2023
Cited by 3 | Viewed by 1827
Abstract
Bi2MoO6 was one of the important bismuth-based semiconductors with a narrow bandgap, and has been widely used in selective oxidation catalysts, supercapacitors, and energy-storage devices. A series of Bi2MoO6/ZnO composite photocatalysts with different mass ratios were [...] Read more.
Bi2MoO6 was one of the important bismuth-based semiconductors with a narrow bandgap, and has been widely used in selective oxidation catalysts, supercapacitors, and energy-storage devices. A series of Bi2MoO6/ZnO composite photocatalysts with different mass ratios were synthesized by the hydrothermal method. The synthesized samples were characterized by XRD, PL, UV-Vis, SEM, TEM, XPS, and BET analysis techniques. Under visible light conditions, Methylene blue (MB) was used as the target degradation product to evaluate its photocatalytic performance. The results showed that the degradation rate constant of Bi2MoO6/ZnO (0.4-BZO) was about twice that of the traditional photocatalysis of ZnO. The Bi2MoO6/ZnO composite catalyst maintained stable performance after four consecutive runs. The high photocatalytic activity of Bi2MoO6/ZnO was attributed to the efficient electron transport of the heterojunction, which accelerates the separation of electron-hole pairs and reduces the probability of carrier recombination near the Bi2MoO6/ZnO heterojunction. Bi2MoO6/ZnO nanocomposites have potential applications in the field of photodegradation. Full article
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10 pages, 2289 KiB  
Article
A Low Driving-Voltage Hybrid-Electrolyte Electrochromic Window with Only Ferreous Redox Couples
by Jisheng Song, Bingkun Huang, Yinyingjie Xu, Kunjie Yang, Yingfan Li, Yuqi Mu, Lingyu Du, Shan Yun and Litao Kang
Nanomaterials 2023, 13(1), 213; https://doi.org/10.3390/nano13010213 - 3 Jan 2023
Cited by 3 | Viewed by 1764
Abstract
Even after decades of development, the widespread application of electrochromic windows (ECW) is still seriously restricted by their high price and inadequate performance associated with structural/fabrication complexity and electrochemical instability. Herein, a simple hybrid electrochromic system based on PFSA (perfluorosulfonic acid)-coated Prussian blue [...] Read more.
Even after decades of development, the widespread application of electrochromic windows (ECW) is still seriously restricted by their high price and inadequate performance associated with structural/fabrication complexity and electrochemical instability. Herein, a simple hybrid electrochromic system based on PFSA (perfluorosulfonic acid)-coated Prussian blue (PB, Fe4III [FeII(CN)6]3) film and Ferricyanide–Ferrocyanide ([Fe(CN)6]4−/[Fe(CN)6]3−)-containing hybrid electrolyte is reported. The PB film and the [Fe(CN)6]4−/[Fe(CN)6]3− couple show near redox potentials well inside the electrochemical window of water, resulting in a low driven voltage (0.4 V for coloring and −0.6 V for bleaching) and a relatively long lifespan (300 cycles with 76.9% transmittance contrast retained). The PFSA layer, as a cation-exchange structure, significantly improves the transmittance modulation amplitude (ΔT: 23.3% vs. 71.9% at a wavelength of 633 nm) and optical memory abilities (ΔT retention: 10.1% vs. 67.0% after 300 s open-circuit rest increases) of the device, by means of preventing the direct contact and charge transfer between the PB film and the [Fe(CN)6]4−/[Fe(CN)6]3− couple. This “hybrid electrolyte + electron barrier layer” design provides an effective way for the construction of simple structured electrochromic devices. Full article
(This article belongs to the Special Issue Nanomaterials in Smart Energy-Efficient Coatings)
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15 pages, 3995 KiB  
Communication
Synthesis of fluorescent Molecularly Imprinted Polymer Nanoparticles Sensing Small Neurotransmitters with High Selectivity Using Immobilized Templates with Regulated Surface Density
by Yasuo Yoshimi, Yuto Katsumata, Naoya Osawa, Neo Ogishita and Ryota Kadoya
Nanomaterials 2023, 13(1), 212; https://doi.org/10.3390/nano13010212 - 3 Jan 2023
Cited by 1 | Viewed by 9122
Abstract
To develop nanosensors to probe neurotransmitters, we synthesized fluorescent-functionalized molecularly imprinted polymeric nanoparticles (fMIP-NPs) using monoamine neurotransmitters (serotonin and dopamine) immobilized on glass beads as templates. The size and fluorescence intensity of the fMIP-NPs synthesized with blended silane couplers increased with the presence [...] Read more.
To develop nanosensors to probe neurotransmitters, we synthesized fluorescent-functionalized molecularly imprinted polymeric nanoparticles (fMIP-NPs) using monoamine neurotransmitters (serotonin and dopamine) immobilized on glass beads as templates. The size and fluorescence intensity of the fMIP-NPs synthesized with blended silane couplers increased with the presence of the target but were insensitive to the target analogs (L-tryptophan and L-dopa, respectively). However, when the template is anchored by a pure silane agent, both the fluorescence intensity and particle size of the fMIP-NPs were sensitive to the structural analog of the template. Another fMIP-NP was synthesized in the presence of poly([2-(methacryloyloxy)ethyl] trimethylammonium chloride (METMAC)-co-methacrylamide) grafted onto glass beads as a dummy template for acetylcholine. Acetylcholine increased the diameter and fluorescence intensity of the fMIP-NP, but choline had no effect. When the homopolymer of METMAC was used as a template, the fluorescence intensity and size of the resulting nanoparticles were not responsive to either acetylcholine or choline. The principle of increased fluorescence intensity due to specific interaction with the target substance is probably due to the increased distance between the fluorescent functional groups and decreased self-quenching due to the swelling caused by the specific interaction with the template. The results also indicate that MIP nanoparticles prepared by solid-phase synthesis can be used for targeting small molecules, such as the neurotransmitters addressed in this study, by adjusting the surface density of the template. Full article
(This article belongs to the Special Issue Advances in Molecularly Imprinted Polymer Nanomaterials)
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19 pages, 6286 KiB  
Article
Significantly Suppressed Dielectric Loss and Enhanced Breakdown Strength in Core@Shell Structured Ni@TiO2/PVDF Composites
by Juanjuan Zhou, Wenying Zhou, Mengxue Yuan, Xinbo Dong, Jiebing Zhang, Xuejiao Zhang, Yanqing Zhang, Xiaolong Chen, Yanrong Chen and Xiangrong Liu
Nanomaterials 2023, 13(1), 211; https://doi.org/10.3390/nano13010211 - 3 Jan 2023
Cited by 7 | Viewed by 1722
Abstract
An insulating shell on the surface of conductive particles is vital for restraining the dielectric loss and leakage current of polymer composites. So as to inhibit the enormous loss and conductivity of pristine nickel (Ni)/poly(vinylidene fluoride)(PVDF) composites but still harvest a high dielectric [...] Read more.
An insulating shell on the surface of conductive particles is vital for restraining the dielectric loss and leakage current of polymer composites. So as to inhibit the enormous loss and conductivity of pristine nickel (Ni)/poly(vinylidene fluoride)(PVDF) composites but still harvest a high dielectric permittivity (εr) when filler loading approaches or exceeds the percolation threshold (fc), pristine Ni particles were covered by a layer of titanium dioxide (TiO2) shell via a sol–gel approach, and then they were composited with PVDF. The impacts of the TiO2 coating on the dielectric performances of the Ni/PVDF composites were explored as a function of the filler concentration, the shell thickness and frequency. In addition, the dielectric performances were fitted using the Havriliak–Negami (H–N) equation in order to further understand the TiO2 shell’s effect on polarization mechanism in the composites. The Ni@TiO2/PVDF composites exhibit high εr and enhanced breakdown strength (Eb) but remarkably suppressed loss and conductivity when compared with pristine Ni/PVDF because the TiO2 shell can efficiently stop the direct contact between Ni particles thereby suppressing the long–range electron transportation. Further, the dielectric performances can be effectively tuned through finely adjusting the TiO2 shell’ thickness. The resulting Ni@TiO2/PVDF composites with high εr and Eb but low loss show appealing applications in microelectronics and electrical fields. Full article
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15 pages, 2031 KiB  
Article
Parylene-Sealed Perovskite Nanocrystals Down-Shifting Layer for Luminescent Spectral Matching in Thin Film Photovoltaics
by Ana Pinheiro, Andreia Ruivo, João Rocha, Marta Ferro, Joana Vaz Pinto, Jonas Deuermeier, Tiago Mateus, Ana Santa, Manuel J. Mendes, Rodrigo Martins, Sandra Gago, César A. T. Laia and Hugo Águas
Nanomaterials 2023, 13(1), 210; https://doi.org/10.3390/nano13010210 - 3 Jan 2023
Cited by 3 | Viewed by 2723
Abstract
The present contribution aims to enhance solar cells’ performance via the development of advanced luminescent down-shifting based on encapsulated nanostructured perovskite materials. Here, thin films of inorganic lead halide (CsPbBr3) perovskite nanocrystal luminophores were synthetized, by hot-injection, deposited on glass substrates [...] Read more.
The present contribution aims to enhance solar cells’ performance via the development of advanced luminescent down-shifting based on encapsulated nanostructured perovskite materials. Here, thin films of inorganic lead halide (CsPbBr3) perovskite nanocrystal luminophores were synthetized, by hot-injection, deposited on glass substrates by spin-coating, and encapsulated with parylene type C, via chemical vapor deposition, to protect and stabilize the films. The optical properties of these thin films were characterized by absorption, emission and 2D contour spectra, their structure by X-ray diffraction and X-ray photoelectron spectroscopy, and the morphology by Scanning Transmission Electron microscopy. I–V curve and spectral response nanocrystalline silicon photovoltaic (nc-Si:H PV) cells were studied in the absence and presence of the perovskite and parylene luminescent down-shifting layers. The incorporation of the CsPbBr3 nanocrystals and their encapsulation with the parylene type C polymeric coating led to an increase in the current generated and the spectral response of the PV cells in the regime of the nanocrystals’ fluorescence emission. A 3.1% increase in the short circuit current density and a 5.6% increase in the power conversion efficiency were observed. Full article
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14 pages, 3318 KiB  
Article
Biogenic Synthesis of Fluorescent Carbon Dots (CDs) and Their Application in Bioimaging of Agricultural Crops
by Akshay M. Pete, Pramod U. Ingle, Rajesh W. Raut, Sudhir S. Shende, Mahendra Rai, Tatiana M. Minkina, Vishnu D. Rajput, Valery P. Kalinitchenko and Aniket K. Gade
Nanomaterials 2023, 13(1), 209; https://doi.org/10.3390/nano13010209 - 3 Jan 2023
Cited by 6 | Viewed by 2300
Abstract
Fluorescent nanoparticles have a transformative potential for advanced sensors and devices for point-of-need diagnostics and bioimaging, bypassing the technical burden of meeting the assay performance requirements. Carbon dots (CDs) are rapidly emerging carbon-based nanomaterials. Regardless of their fate, they will find increasing applications. [...] Read more.
Fluorescent nanoparticles have a transformative potential for advanced sensors and devices for point-of-need diagnostics and bioimaging, bypassing the technical burden of meeting the assay performance requirements. Carbon dots (CDs) are rapidly emerging carbon-based nanomaterials. Regardless of their fate, they will find increasing applications. In this study, a simple approach for synthesizing CDs from fruit peels was developed. The CDs were fabricated from Annona squamosa (L.) peels using a carbonization technique through microwave-assisted hydrothermal digestion at temperatures around 200 °C. Synthesized CDs were detected using a UV transilluminator for the preliminary confirmation of the presence of fluorescence. UV–Vis spectrophotometry (absorbance at 505 nm) analysis, zeta potential measurement (−20.8 mV), nanoparticles tracking analysis (NTA) (average size: 15.4 nm and mode size: 9.26 nm), photoluminescence, and Fourier transform infrared (FT-IR) analysis were used to identify the capping functional groups on the CDs. The total quantum yield exhibited was 8.93%, and the field emission scanning electron microscopy (FESEM) showed the size range up to 40 nm. The germinating mung bean (Vigna radiata (L.)) seeds were incubated with biogenically synthesized CDs to check the absorption of CDs by them. The fluorescence was observed under a UV-transilluminator in the growing parts of seeds, indicating the absorption of CDs during the germination, development, and growth. These fluorescent CDs could be used as a bioimaging agent. This novel method of synthesizing CDs was found to be eco-friendly, rapid, and cost-effective. Full article
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12 pages, 4161 KiB  
Article
Characterization of Magnetron Sputtered BiTe-Based Thermoelectric Thin Films
by Zhenxue Zhang, Mikdat Gurtaran, Xiaoying Li, Hio-Ieng Un, Yi Qin and Hanshan Dong
Nanomaterials 2023, 13(1), 208; https://doi.org/10.3390/nano13010208 - 3 Jan 2023
Cited by 3 | Viewed by 1854
Abstract
Thermoelectric (TE) technology attracts much attention due to the fact it can convert thermal energy into electricity and vice versa. Thin-film TE materials can be synthesized on different kinds of substrates, which offer the possibility of the control of microstructure and composition to [...] Read more.
Thermoelectric (TE) technology attracts much attention due to the fact it can convert thermal energy into electricity and vice versa. Thin-film TE materials can be synthesized on different kinds of substrates, which offer the possibility of the control of microstructure and composition to higher TE power, as well as the development of novel TE devices meeting flexible and miniature requirements. In this work, we use magnetron sputtering to deposit N-type and P-type BiTe-based thin films on silicon, glass, and Kapton HN polyimide foil. Their morphology, microstructure, and phase constituents are studied by SEM/EDX, XRD, and TEM. The electrical conductivity, thermal conductivity, and Seebeck coefficient of the thin film are measured by a special in-plane advanced test system. The output of electrical power (open-circuit voltage and electric current) of the thin film is measured by an in-house apparatus at different temperature gradient. The impact of deposition parameters and the thickness, width, and length of the thin film on the power output are also investigated for optimizing the thin-film flexible TE device to harvest thermal energy. Full article
(This article belongs to the Special Issue Nanostructured Materials for Energy Applications)
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3 pages, 183 KiB  
Editorial
Nanomaterials for Drug Delivery and Cancer Therapy
by Fiore Pasquale Nicoletta and Francesca Iemma
Nanomaterials 2023, 13(1), 207; https://doi.org/10.3390/nano13010207 - 3 Jan 2023
Cited by 2 | Viewed by 1894
Abstract
In recent decades, the interest in nanomaterials has grown rapidly for their applications in many research fields, including drug delivery and cancer therapy [...] Full article
(This article belongs to the Special Issue Nanomaterials for Drug Delivery and Cancer Therapy)
4 pages, 203 KiB  
Editorial
Multifunctional Magnetic Nanocomposites: Innovative Processing and Applications
by Victor Kuncser
Nanomaterials 2023, 13(1), 206; https://doi.org/10.3390/nano13010206 - 3 Jan 2023
Viewed by 1327
Abstract
Multifunctional magnetic nanocomposites are among those heterogeneous nanosized systems where at least one phase component is magnetic and can act as an intermediate of either the actuation or the response of the overall system. The main advantage of heterogeneous nanosystems is the possibility [...] Read more.
Multifunctional magnetic nanocomposites are among those heterogeneous nanosized systems where at least one phase component is magnetic and can act as an intermediate of either the actuation or the response of the overall system. The main advantage of heterogeneous nanosystems is the possibility of combining and inter-influencing the electronic properties of constituent interfaced nanophases. Consequently, unique physico-chemical properties of the hybrid materials of interest in various applications can be obtained. This Special Issue of Nanomaterials highlights the most advanced processing and characterization tools of some multifunctional magnetic nanocomposites and heterogeneous systems of interest in various applications, from biomedicine to sensoristics and energy-saving materials. Full article
14 pages, 6255 KiB  
Article
Effect of Polyphenols on the Ice-Nucleation Activity of Ultrafine Bubbles
by Tsutomu Uchida and Yukiharu Fukushi
Nanomaterials 2023, 13(1), 205; https://doi.org/10.3390/nano13010205 - 2 Jan 2023
Cited by 2 | Viewed by 2230
Abstract
Ultrafine bubbles (UFBs) in water provide a large amount of gas and a large gas–liquid interfacial area, and can release energy through their collapse. Such features may promote ice nucleation. Here, we examined the nucleation of ice in solutions containing polyphenols and UFBs. [...] Read more.
Ultrafine bubbles (UFBs) in water provide a large amount of gas and a large gas–liquid interfacial area, and can release energy through their collapse. Such features may promote ice nucleation. Here, we examined the nucleation of ice in solutions containing polyphenols and UFBs. To reduce the likelihood of nucleation occurring on the container walls over that in previous studies, we used a much larger sample volume of 1 mL. In our experiments, UFBs (when present) had a number concentration of 108 mL−1. We quantified changes to the nucleation activity by examining the shift in the cumulative freezing (nucleation) probability distribution. Compared to pure water, this freezing curve shifts approximately 0.6 °C higher with the UFBs. Then, to the water, we added three polyphenols (tannic acid TA, tea catechin TC, and oligonol OLG), chosen because they had been reported to reduce the ice-nucleation activity of heterogeneous ice nuclei (e.g., AgI). We found experimentally that, without UFBs, all polyphenols instead shift the pure-water freezing curve to a higher temperature. Then, when UFBs are added, the additional temperature shift in the freezing curve is slightly higher for OLG, essentially unchanged for TA, and slightly lower for TC. To help to explain these differences, we examined the UFB size distributions using dynamic light scattering and freeze-fractured replicas with transmission electron microscopy, finding that OLG and TC alter the UFBs, but that TA does not. Full article
(This article belongs to the Special Issue Nanobubbles and Their Applications)
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23 pages, 9845 KiB  
Review
Electrospinning Inorganic Nanomaterials to Fabricate Bionanocomposites for Soft and Hard Tissue Repair
by Jie Cui, Xiao Yu, Yihong Shen, Binbin Sun, Wanxin Guo, Mingyue Liu, Yujie Chen, Li Wang, Xingping Zhou, Muhammad Shafiq and Xiumei Mo
Nanomaterials 2023, 13(1), 204; https://doi.org/10.3390/nano13010204 - 2 Jan 2023
Cited by 13 | Viewed by 2355
Abstract
Tissue engineering (TE) has attracted the widespread attention of the research community as a method of producing patient-specific tissue constructs for the repair and replacement of injured tissues. To date, different types of scaffold materials have been developed for various tissues and organs. [...] Read more.
Tissue engineering (TE) has attracted the widespread attention of the research community as a method of producing patient-specific tissue constructs for the repair and replacement of injured tissues. To date, different types of scaffold materials have been developed for various tissues and organs. The choice of scaffold material should take into consideration whether the mechanical properties, biodegradability, biocompatibility, and bioresorbability meet the physiological properties of the tissues. Owing to their broad range of physico-chemical properties, inorganic materials can induce a series of biological responses as scaffold fillers, which render them a good alternative to scaffold materials for tissue engineering (TE). While it is of worth to further explore mechanistic insight into the use of inorganic nanomaterials for tissue repair, in this review, we mainly focused on the utilization forms and strategies for fabricating electrospun membranes containing inorganic components based on electrospinning technology. A particular emphasis has been placed on the biological advantages of incorporating inorganic materials along with organic materials as scaffold constituents for tissue repair. As well as widely exploited natural and synthetic polymers, inorganic nanomaterials offer an enticing platform to further modulate the properties of composite scaffolds, which may help further broaden the application prospect of scaffolds for TE. Full article
(This article belongs to the Special Issue Applications of Electrospinning-Based 3D Architecture Nanomaterials)
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15 pages, 6866 KiB  
Article
Improving Bond Performance and Reducing Cross-Linker Dosage of Soy Protein Adhesive via Hyper-Branched and Organic–Inorganic Hybrid Structures
by Zheng Cui, Yecheng Xu, Gang Sun, Lai Peng, Jianzhang Li, Jing Luo and Qiang Gao
Nanomaterials 2023, 13(1), 203; https://doi.org/10.3390/nano13010203 - 2 Jan 2023
Viewed by 1849
Abstract
Eco-friendly soybean protein adhesives could be an ideal substitute for replacing traditional formaldehyde-based adhesives in wood industry. However, a large number of cross-linking agents are required in soy protein adhesive formulations to obtain sufficiently performing properties. Inspired by the high performance of nacre [...] Read more.
Eco-friendly soybean protein adhesives could be an ideal substitute for replacing traditional formaldehyde-based adhesives in wood industry. However, a large number of cross-linking agents are required in soy protein adhesive formulations to obtain sufficiently performing properties. Inspired by the high performance of nacre and branched structures, a hyper-branched amine (HBPA) was synthesized and grafted to graphene oxide (GO), generating a hyper-branched amine-functionalized GO (FGO). A novel soy protein-based adhesive was developed by mixing FGO with soy protein (SPI) and a low dose polyamidoamine-epichlorohydrin (PAE). Results showed that the addition of only 0.4 wt% FGO and 0.75 wt% PAE to the SPI adhesive formulation enhanced the wet shear strength of plywood to 1.18 MPa, which was 181% higher than that of the adhesive without enhancement. The enhanced performance is attributed to the denser cross-linking structure and improved toughness of the adhesive layer. Using FGO in the adhesive formulation also greatly reduced the concentration of the additive cross-linker by up to 78.6% when compared with values reported in the literature. Thus, using a hyper-branched functionalized nano-material to form an organic–inorganic hybrid structure is an effective and efficient strategy to reinforce the composites and polymers. It significantly reduces the chemical additive levels, and is a practical way to develop a sustainable product. Full article
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12 pages, 3056 KiB  
Article
Preparation of 2D ZIF-L and Its Antibacterial and Antifouling Properties
by Jingyu Li, Yang Zhang, Haichao Zhao and Guoxin Sui
Nanomaterials 2023, 13(1), 202; https://doi.org/10.3390/nano13010202 - 2 Jan 2023
Cited by 2 | Viewed by 2283
Abstract
The excessively leached metal ions from traditional metallic antimicrobial nanoparticles are harmful to biological and human tissues. Metal-organic frameworks (MOFs) coordinating bioactive metal ions to organic bridging ligands can potentially address this issue, avoiding the excessive leaching of metal ions and simultaneously exhibiting [...] Read more.
The excessively leached metal ions from traditional metallic antimicrobial nanoparticles are harmful to biological and human tissues. Metal-organic frameworks (MOFs) coordinating bioactive metal ions to organic bridging ligands can potentially address this issue, avoiding the excessive leaching of metal ions and simultaneously exhibiting high effective antibacterial activities. Here, we report the preparation of a 2-dimensional leaves-like zeolitic imidazolate framework (ZIF-L) for potential antibacterial and anti-algae applications. The ZIF-L nanosheet exhibits complete inactivation of Escherichia coli (phosphate buffer saline: 4 h) and Bacillus subtilis (seawater: 0.5 h). The ZIF-L/epoxy composite has excellent antibacterial effect, poisoning effect and anti-adhesion effect on a variety of marine algae. It is worth noting that the removal rate (Escherichia coli) for ZIF/epoxy composite can be reached to 90.20% by only adding ZIF-L (0.25 wt%). This work will inspire researchers to develop more metal-organic frameworks materials for applications in the antibacterial and anti-algae fields. Full article
(This article belongs to the Section Nanocomposite Materials)
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18 pages, 2130 KiB  
Article
Advances in the Mechanistic Understanding of Iron Oxide Nanoparticles’ Radiosensitizing Properties
by Indiana Ternad, Sebastien Penninckx, Valentin Lecomte, Thomas Vangijzegem, Louise Conrard, Stéphane Lucas, Anne-Catherine Heuskin, Carine Michiels, Robert N. Muller, Dimitri Stanicki and Sophie Laurent
Nanomaterials 2023, 13(1), 201; https://doi.org/10.3390/nano13010201 - 2 Jan 2023
Cited by 7 | Viewed by 2037
Abstract
Among the plethora of nanosystems used in the field of theranostics, iron oxide nanoparticles (IONPs) occupy a central place because of their biocompatibility and magnetic properties. In this study, we highlight the radiosensitizing effect of two IONPs formulations (namely 7 nm carboxylated IONPs [...] Read more.
Among the plethora of nanosystems used in the field of theranostics, iron oxide nanoparticles (IONPs) occupy a central place because of their biocompatibility and magnetic properties. In this study, we highlight the radiosensitizing effect of two IONPs formulations (namely 7 nm carboxylated IONPs and PEG5000-IONPs) on A549 lung carcinoma cells when exposed to 225 kV X-rays after 6 h, 24 h and 48 h incubation. The hypothesis that nanoparticles exhibit their radiosensitizing effect by weakening cells through the inhibition of detoxification enzymes was evidenced by thioredoxin reductase activity monitoring. In particular, a good correlation between the amplification effect at 2 Gy and the residual activity of thioredoxin reductase was observed, which is consistent with previous observations made for gold nanoparticles (NPs). This emphasizes that NP-induced radiosensitization does not result solely from physical phenomena but also results from biological events. Full article
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23 pages, 6009 KiB  
Article
Zein Nanoparticles Containing Arginine-Phenylalanine-Based Surfactants: Stability, Antimicrobial and Hemolytic Activity
by Lourdes Perez, Zakaria Hafidi, Aurora Pinazo, Maria Teresa García, Manuel Martín-Pastor and Francisco Fábio Oliveira de Sousa
Nanomaterials 2023, 13(1), 200; https://doi.org/10.3390/nano13010200 - 2 Jan 2023
Cited by 4 | Viewed by 1843
Abstract
Although cationic surfactants have a remarkable antimicrobial activity, they present an intrinsic toxicity that discourages their usage. In this work novel zein nanoparticles loaded with arginine-phenylalanine-based surfactants are presented. The nanoparticles were loaded with two single polar head (LAM and PNHC12) [...] Read more.
Although cationic surfactants have a remarkable antimicrobial activity, they present an intrinsic toxicity that discourages their usage. In this work novel zein nanoparticles loaded with arginine-phenylalanine-based surfactants are presented. The nanoparticles were loaded with two single polar head (LAM and PNHC12) and two with double amino acid polar head surfactants, arginine-phenylalanine (C12PAM, PANHC12). The formulations were characterized and their stability checked up to 365 days. Furthermore, the antimicrobial and hemolytic activities were investigated. Finally, NMR and molecular docking studies were carried out to elucidate the possible interaction mechanisms of surfactant-zein. The nanoparticles were obtained with satisfactory size, zeta potential and dispersibility. The surfactants containing arginine-phenylalanine residues were found to be more stable. The nanoencapsulation maintained the antimicrobial activities unaltered in comparison to the surfactants’ solutions. These results are in agreement with the NMR and docking findings, suggesting that zein interacts with the surfactants by the aromatic rings of phenylalanine. As a result, the cationic charges and part of the aliphatic chains are freely available to attack the bacteria and fungi, while not available to disrupt the cellular membranes. This approach opens new possibilities for using cationic surfactants and benefits from their extraordinary antimicrobial responses for several applications. Full article
(This article belongs to the Special Issue Functional Nanoparticles for Biomedical and Nanomedicine Application)
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9 pages, 4851 KiB  
Communication
A Novel Controlled Fabrication of Hexagonal Boron Nitride Incorporated Composite Granules Using the Electrostatic Integrated Granulation Method
by Taisei Nakazono, Atsushi Yokoi, Wai Kian Tan, Go Kawamura, Atsunori Matsuda and Hiroyuki Muto
Nanomaterials 2023, 13(1), 199; https://doi.org/10.3390/nano13010199 - 2 Jan 2023
Cited by 1 | Viewed by 1579
Abstract
Despite the availability of nano and submicron-sized additive materials, the controlled incorporation and utilization of these additives remain challenging due to their difficult handling ability and agglomeration-prone properties. The formation of composite granules exhibiting unique microstructure with desired additives distribution and good handling [...] Read more.
Despite the availability of nano and submicron-sized additive materials, the controlled incorporation and utilization of these additives remain challenging due to their difficult handling ability and agglomeration-prone properties. The formation of composite granules exhibiting unique microstructure with desired additives distribution and good handling ability has been reported using the electrostatic integrated granulation method. This study demonstrates the feasible controlled incorporation of two-dimensional hexagonal boron nitride (hBN) sheets with alumina (Al2O3) particles, forming Al2O3–hBN core–shell composite granules. The sintered artifacts obtained using Al2O3–hBN core–shell composite granules exhibited an approximately 28% higher thermal conductivity than those obtained using homogeneously hBN-incorporated Al2O3 composite granules. The findings from this study would be beneficial for developing microstructurally controlled composite granules with the potential for scalable fabrication via powder-metallurgy inspired methods. Full article
(This article belongs to the Special Issue Boron Nitride-Based Nanomaterials)
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9 pages, 3216 KiB  
Article
First Order Rate Law Analysis for Reset State in Vanadium Oxide Thin Film Resistive Random Access Memory Devices
by Kai-Huang Chen, Chien-Min Cheng, Na-Fu Wang, Hsiao-Wen Hung, Cheng-Ying Li and Sean Wu
Nanomaterials 2023, 13(1), 198; https://doi.org/10.3390/nano13010198 - 1 Jan 2023
Cited by 3 | Viewed by 1787
Abstract
In the reset state, the decay reaction mechanism and bipolar switching properties of vanadium oxide thin film RRAM devices for LRS/HRS are investigated and discussed here. To discover the properties of I-V switching curves, the first order rate law behaviors of the reset [...] Read more.
In the reset state, the decay reaction mechanism and bipolar switching properties of vanadium oxide thin film RRAM devices for LRS/HRS are investigated and discussed here. To discover the properties of I-V switching curves, the first order rate law behaviors of the reset state between the resistant variety properties and the reaction time were observed. To verify the decay reaction mechanism in the reset state, vanadium oxide thin films from RRAM devices were measured by different constant voltage sampling and exhibited the same decay reaction rate constant. Finally, the electrical conduction transfer mechanism and metallic filament forming model described by I-V switching properties of the RRAM devices were proven and investigated. Full article
(This article belongs to the Special Issue Nano-Structured Thin Films: Growth, Characteristics, and Application)
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14 pages, 3573 KiB  
Article
Fabrication of Li-Doped NiO Thin Films by Ultrasonic Spray Pyrolysis and Its Application in Light-Emitting Diodes
by Víctor Hugo López-Lugo, Manuel García-Hipólito, Arturo Rodríguez-Gómez and Juan Carlos Alonso-Huitrón
Nanomaterials 2023, 13(1), 197; https://doi.org/10.3390/nano13010197 - 1 Jan 2023
Cited by 6 | Viewed by 2507
Abstract
The fabrication of NiO films by different routes is important to extend and improve their applications as hole-transporting layers in organic and inorganic optoelectronic devices. Here, an automated ultrasonic pyrolysis spray method was used to fabricate NiO and Li-doped NiO thin films using [...] Read more.
The fabrication of NiO films by different routes is important to extend and improve their applications as hole-transporting layers in organic and inorganic optoelectronic devices. Here, an automated ultrasonic pyrolysis spray method was used to fabricate NiO and Li-doped NiO thin films using nickel acetylacetonate and lithium acetate dihydrate as metal precursor and dimethylformamide as solvent. The effect of the amount of lithium in the precursor solution on the structural, morphological, optical, and electrical properties were studied. XRD results reveal that all the samples are polycrystalline with cubic structure and crystallite sizes in the range of 21 to 25 nm, without any clear trend with the Li doping level. AFM analysis shows that the crystallites form round-shaped aggregates and all the films have low roughness. The optical transmittance of the films reaches values of 60% to 77% with tendency upward as Li content is increased. The electrical study shows that the films are p-type, with the carrier concentration, resistivity, and carrier mobility depending on the lithium doping. NiO:Li (10%) films were successfully incorporated into inorganic light emitting diodes together with Mn-doped ZnS and ZnO:Al films, all deposited on ITO by the same ultrasonic spray pyrolysis technique. Full article
(This article belongs to the Special Issue Nanostructured Materials for Energy Applications)
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18 pages, 2991 KiB  
Article
Investigations of Optical Functions and Optical Transitions of 2D Semiconductors by Spectroscopic Ellipsometry and DFT
by Honggang Gu, Zhengfeng Guo, Liusheng Huang, Mingsheng Fang and Shiyuan Liu
Nanomaterials 2023, 13(1), 196; https://doi.org/10.3390/nano13010196 - 1 Jan 2023
Cited by 2 | Viewed by 2019
Abstract
Optical functions and transitions are essential for a material to reveal the light–matter interactions and promote its applications. Here, we propose a quantitative strategy to systematically identify the critical point (CP) optical transitions of 2D semiconductors by combining the spectroscopic ellipsometry (SE) and [...] Read more.
Optical functions and transitions are essential for a material to reveal the light–matter interactions and promote its applications. Here, we propose a quantitative strategy to systematically identify the critical point (CP) optical transitions of 2D semiconductors by combining the spectroscopic ellipsometry (SE) and DFT calculations. Optical functions and CPs are determined by SE, and connected to DFT band structure and projected density of states via equal-energy and equal-momentum lines. The combination of SE and DFT provides a powerful tool to investigate the CP optical transitions, including the transition energies and positions in Brillouin zone (BZ), and the involved energy bands and carries. As an example, the single-crystal monolayer WS2 is investigated by the proposed method. Results indicate that six excitonic-type CPs can be quantitatively distinguished in optical function of the monolayer WS2 over the spectral range of 245–1000 nm. These CPs are identified as direct optical transitions from three highest valence bands to three lowest conduction bands at high symmetry points in BZ contributed by electrons in S-3p and W-5d orbitals. Results and discussion on the monolayer WS2 demonstrate the effectiveness and advantages of the proposed method, which is general and can be easily extended to other materials. Full article
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13 pages, 2743 KiB  
Article
Metal-Dielectric Nanopillar Antenna-Resonators for Efficient Collected Photon Rate from Silicon Carbide Color Centers
by Faraz Ahmed Inam and Stefania Castelletto
Nanomaterials 2023, 13(1), 195; https://doi.org/10.3390/nano13010195 - 1 Jan 2023
Cited by 3 | Viewed by 1794
Abstract
A yet unresolved challenge in developing quantum technologies based on color centres in high refractive index semiconductors is the efficient fluorescence enhancement of point defects in bulk materials. Optical resonators and antennas have been designed to provide directional emission, spontaneous emission rate enhancement [...] Read more.
A yet unresolved challenge in developing quantum technologies based on color centres in high refractive index semiconductors is the efficient fluorescence enhancement of point defects in bulk materials. Optical resonators and antennas have been designed to provide directional emission, spontaneous emission rate enhancement and collection efficiency enhancement at the same time. While collection efficiency enhancement can be achieved by individual nanopillars or nanowires, fluorescent emission enhancement is achieved using nanoresonators or nanoantennas. In this work, we optimise the design of a metal-dielectric nanopillar-based antenna/resonator fabricated in a silicon carbide (SiC) substrate with integrated quantum emitters. Here we consider various color centres known in SiC such as silicon mono-vacancy and the carbon antisite vacancy pair, that show single photon emission and quantum sensing functionalities with optical electron spin read-out, respectively. We model the dipole emission fluorescence rate of these color centres into the metal-dielectric nanopillar hybrid antenna resonator using multi-polar electromagnetic scattering resonances and near-field plasmonic field enhancement and confinement. We calculate the fluorescence collected photon rate enhancement for these solid state vacancy-centers in SiC in these metal-dielectric nanopillar resonators, showing a trade-off effect between the collection efficiency and radiative Purcell factor enhancement. We obtained a collected photon rate enhancement from a silicon monovacancy vacancy center embedded in an optimised hybrid antenna-resonator two orders of magnitude larger compared to the case of the color centres in bulk material. Full article
(This article belongs to the Section Theory and Simulation of Nanostructures)
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10 pages, 2935 KiB  
Article
Improved Electrical Properties of EHD Jet-Patterned MoS2 Thin-Film Transistors with Printed Ag Electrodes on a High-k Dielectric
by Thi Thu Thuy Can and Woon-Seop Choi
Nanomaterials 2023, 13(1), 194; https://doi.org/10.3390/nano13010194 - 1 Jan 2023
Cited by 5 | Viewed by 1809
Abstract
Electrohydrodynamic (EHD) jet printing is known as a versatile method to print a wide viscosity range of materials that are impossible to print by conventional inkjet printing. Hence, with the understanding of the benefits of EHD jet printing, solution-based MoS2 and a [...] Read more.
Electrohydrodynamic (EHD) jet printing is known as a versatile method to print a wide viscosity range of materials that are impossible to print by conventional inkjet printing. Hence, with the understanding of the benefits of EHD jet printing, solution-based MoS2 and a high-viscosity Ag paste were EHD jet-printed for electronic applications in this work. In particular, printed MoS2 TFTs with a patterned Ag source and drain were successfully fabricated with low-k silica (SiO2) and high-k alumina (Al2O3) gate dielectrics, respectively. Eventually, the devices based on Al2O3 exhibited much better electrical properties compared to the ones based on SiO2. Interestingly, an improvement of around one order of magnitude in hysteresis was achieved for devices after changing the gate insulator from SiO2 to Al2O3. In effect, the results of this work for the printed MoS2 and the printed Ag source and drains for TFTs demonstrate a new approach for jet printing in the fabrication of electronic devices. Full article
(This article belongs to the Special Issue 2D Semiconducting Materials for Device Applications)
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15 pages, 3822 KiB  
Article
Enhancing the Performance of the Photonic Integrated Sensing System by Applying Frequency Interrogation
by Grigory S. Voronkov, Yana V. Aleksakina, Vladislav V. Ivanov, Aida G. Zakoyan, Ivan V. Stepanov, Elizaveta P. Grakhova, Muhammad A. Butt and Ruslan V. Kutluyarov
Nanomaterials 2023, 13(1), 193; https://doi.org/10.3390/nano13010193 - 1 Jan 2023
Cited by 7 | Viewed by 1929
Abstract
Lab-on-a-chip systems are currently one of the most promising areas in the development of ultra-compact sensor systems, used primarily for gas and liquid analysis to determine the concentration of impurities. Integrated photonics is an ideal basis for designing “lab-on-a-chip” systems, advantageous for its [...] Read more.
Lab-on-a-chip systems are currently one of the most promising areas in the development of ultra-compact sensor systems, used primarily for gas and liquid analysis to determine the concentration of impurities. Integrated photonics is an ideal basis for designing “lab-on-a-chip” systems, advantageous for its compactness, energy efficiency, and low cost in mass production. This paper presents a solution for “lab-on-a-chip” device realization, consisting of a sensor and an interrogator based on a silicon-on-insulator (SOI) integrated photonics platform. The sensor function is performed by an all-pass microring resonator (MRR), installed as a notch filter in the feedback circuit of an optoelectronic oscillator based on an electro-optic phase modulator. This structure realizes the frequency interrogation of the sensor with high accuracy and speed using a conventional single-mode laser source. The system sensitivity for the considered gases is 13,000 GHz/RIU. The results show that the use of frequency interrogation makes it possible to increase the intrinsic LoD by five orders. The proposed solution opens an opportunity for fully integrated implementation of a photonic “laboratory-on-a-chip” unit. Full article
(This article belongs to the Special Issue Research of Photonics at the Nanometer Scale)
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28 pages, 8082 KiB  
Review
“Stealth Scripts”: Ultrashort Pulse Laser Luminescent Microscale Encoding of Bulk Diamonds via Ultrafast Multi-Scale Atomistic Structural Transformations
by Sergey Kudryashov, Pavel Danilov, Nikita Smirnov, George Krasin, Roman Khmelnitskii, Oleg Kovalchuk, Galina Kriulina, Victor Martovitskiy, Vasily Lednev, Pavel Sdvizhenskii, Yulia Gulina, Elena Rimskaya, Evgeny Kuzmin, Jiajun Chen, Michael Kovalev and Alexey Levchenko
Nanomaterials 2023, 13(1), 192; https://doi.org/10.3390/nano13010192 - 1 Jan 2023
Cited by 9 | Viewed by 1965
Abstract
The ultrashort-laser photoexcitation and structural modification of buried atomistic optical impurity centers in crystalline diamonds are the key enabling processes in the fabrication of ultrasensitive robust spectroscopic probes of electrical, magnetic, stress, temperature fields, and single-photon nanophotonic devices, as well as in “stealth” [...] Read more.
The ultrashort-laser photoexcitation and structural modification of buried atomistic optical impurity centers in crystalline diamonds are the key enabling processes in the fabrication of ultrasensitive robust spectroscopic probes of electrical, magnetic, stress, temperature fields, and single-photon nanophotonic devices, as well as in “stealth” luminescent nano/microscale encoding in natural diamonds for their commercial tracing. Despite recent remarkable advances in ultrashort-laser predetermined generation of primitive optical centers in diamonds even on the single-center level, the underlying multi-scale basic processes, rather similar to other semiconductors and dielectrics, are almost uncovered due to the multitude of the involved multi-scale ultrafast and spatially inhomogeneous optical, electronic, thermal, and structural elementary events. We enlighten non-linear wavelength-, polarization-, intensity-, pulsewidth-, and focusing-dependent photoexcitation and energy deposition mechanisms in diamonds, coupled to the propagation of ultrashort laser pulses and ultrafast off-focus energy transport by electron–hole plasma, transient plasma- and hot-phonon-induced stress generation and the resulting variety of diverse structural atomistic modifications in the diamond lattice. Our findings pave the way for new forthcoming groundbreaking experiments and comprehensive enlightening two-temperature and/or atomistic modeling both in diamonds and other semiconductor/dielectric materials, as well as innovative technological breakthroughs in the field of single-photon source fabrication and “stealth” luminescent nano/microencoding in bulk diamonds for their commercial tracing. Full article
(This article belongs to the Special Issue Nanophotonics Enabled by Femtosecond Lasers)
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16 pages, 43017 KiB  
Article
Design and Optimization of an Ultrathin and Broadband Polarization-Insensitive Fractal FSS Using the Improved Bacteria Foraging Optimization Algorithm and Curve Fitting
by Yaxi Pan and Jian Dong
Nanomaterials 2023, 13(1), 191; https://doi.org/10.3390/nano13010191 - 1 Jan 2023
Cited by 16 | Viewed by 1827
Abstract
A frequency-selective surface (FSS) optimization method combining a curve-fitting technique and an improved bacterial foraging optimization (IBFO) algorithm is proposed. In the method, novel Koch curve-like FSS and Minkowski fractal islands FSS were designed with a desired resonance center frequency and bandwidth. The [...] Read more.
A frequency-selective surface (FSS) optimization method combining a curve-fitting technique and an improved bacterial foraging optimization (IBFO) algorithm is proposed. In the method, novel Koch curve-like FSS and Minkowski fractal islands FSS were designed with a desired resonance center frequency and bandwidth. The bacteria foraging optimization (BFO) algorithm is improved to enhance the performance of the FSS. A curve-fitting technique is provided to allow an intuitive and numerical analysis of the correspondence between the FSS structural parameters and the frequency response. The curve-fitting results are used to evaluate the fitness function of the IBFO algorithm, replacing multiple repeated calls to the electromagnetic simulation software with the curve-fitting equation and thus speeding up the design process. IBFO is compared with the classical BFO algorithm, the hybrid BFO-particle swarm optimization algorithm (BSO), and the artificial bee colony algorithm (ABC) to demonstrate its superior performance. The designed fractal FSS is fabricated and tested to verify the experimental results. The simulation and measurement results show that the proposed FSS has a fractional bandwidth of 91.7% in the frequency range of 3.41–9.19 GHz (S, C, and X-bands). In addition, the structure is very thin, with only 0.025λ and 0.067λ at the lowest and highest frequencies, respectively. The proposed fractal FSS has shown stable performance for both TE and TM polarizations at oblique incidence angles up to 45°. according to simulations and measurements. Full article
(This article belongs to the Special Issue Metamaterials, Nanocomposites and Applications)
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11 pages, 5428 KiB  
Article
In Situ Study of Twin Boundary Stability in Nanotwinned Copper Pillars under Different Strain Rates
by Shou-Yi Chang, Yi-Chung Huang, Shao-Yi Lin, Chia-Ling Lu, Chih Chen and Ming Dao
Nanomaterials 2023, 13(1), 190; https://doi.org/10.3390/nano13010190 - 1 Jan 2023
Cited by 3 | Viewed by 1751
Abstract
The nanoscopic deformation of ⟨111⟩ nanotwinned copper nanopillars under strain rates between 10−5/s and 5 × 10−4/s was studied by using in situ transmission electron microscopy. The correlation among dislocation activity, twin boundary instability due to incoherent twin boundary [...] Read more.
The nanoscopic deformation of ⟨111⟩ nanotwinned copper nanopillars under strain rates between 10−5/s and 5 × 10−4/s was studied by using in situ transmission electron microscopy. The correlation among dislocation activity, twin boundary instability due to incoherent twin boundary migration and corresponding mechanical responses was investigated. Dislocations piled up in the nanotwinned copper, giving rise to significant hardening at relatively high strain rates of 3–5 × 10−4/s. Lower strain rates resulted in detwinning and reduced hardening, while corresponding deformation mechanisms are proposed based on experimental results. At low/ultralow strain rates below 6 × 10−5/s, dislocation activity almost ceased operating, but the migration of twin boundaries via the 1/4 ⟨101¯ ⟩ kink-like motion of atoms is suggested as the detwinning mechanism. At medium strain rates of 1–2 × 10−4/s, detwinning was decelerated likely due to the interfered kink-like motion of atoms by activated partial dislocations, while dislocation climb may alternatively dominate detwinning. These results indicate that, even for the same nanoscale twin boundary spacing, different nanomechanical deformation mechanisms can operate at different strain rates. Full article
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