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12 pages, 1827 KiB

Open AccessArticle

Zwitterionic Functionalization of Persistent Luminescence Nanoparticles: Physicochemical Characterizations and In Vivo Biodistribution in Mice

by Delphine Dassonville, Thomas Lécuyer, Johanne Seguin, Yohann Corvis, Jianhua Liu, Guanyu Cai, Julia Mouton, Daniel Scherman, Nathalie Mignet and Cyrille Richard

Coatings 2023, 13(11), 1913; https://doi.org/10.3390/coatings13111913 - 08 Nov 2023

Viewed by 741

Abstract

After excitation in the biological transparency window, chromium-doped zinc gallate nanoparticles (ZGO NPs) emit near-infrared luminescence for more than an hour, allowing long-term imaging to be performed without background autofluorescence. However, these nanoparticles are recognized in just a few minutes by serum proteins [...] Read more.

After excitation in the biological transparency window, chromium-doped zinc gallate nanoparticles (ZGO NPs) emit near-infrared luminescence for more than an hour, allowing long-term imaging to be performed without background autofluorescence. However, these nanoparticles are recognized in just a few minutes by serum proteins and are then trapped in the liver. In this article, we put forth that liver uptake can be delayed when coating the surface of ZGO NPs with zwitterions. We focused on the use of a very small zwitterion molecule of 330 Da derived from sulfobetaine silane (SBS) and its grafting in one step and in water onto zinc gallate nanoparticles, and we compared the colloidal stability, the in vitro interactions with serum proteins, and the biodistribution in mice with PEGylated ZGO NPs (5000 Da) prepared in two steps in organic solvent. In vitro quantification of serum protein adsorption suggests that the similarity between the sulfobetaine and the cell membrane is enough to reduce protein adsorption as much as a PEGylation, despite the difference in coating thickness and molecular weight. This study has also proved that a combination of good protein repulsion and a smaller size compared to PEGylated NPs allows similar circulation times to be obtained in mice with zwitterionic or PEG coatings. Therefore, its use could offer new opportunities for further in vivo application of functionalized ZGO derivative NPs. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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10 pages, 2412 KiB

Open AccessArticle

Switchable Dual-Functional Metasurface for THz Absorption and Electromagnetically Induced Transparency

by Haocheng Cai, Yue Yang, Jianchen Zi, Luhong Mao and Jining Li

Coatings 2023, 13(5), 816; https://doi.org/10.3390/coatings13050816 - 23 Apr 2023

Cited by 1 | Viewed by 1339

Abstract

The metasurfaces based on nanostructure film play an important role in many fields. Usually, the properties and functions of metasurfaces are limited by their structure. Once the metasurface samples are processed, their functions have already been restricted. The dual-function device designed in this [...] Read more.

The metasurfaces based on nanostructure film play an important role in many fields. Usually, the properties and functions of metasurfaces are limited by their structure. Once the metasurface samples are processed, their functions have already been restricted. The dual-function device designed in this work utilizes the phase transition characteristic of vanadium dioxide (VO₂). The entire layer of VO₂ film is inserted between the double metal micro-nano structure. When VO₂ film is in the metallic state after phase change, an isotropic narrow absorber is obtained in the terahertz (THz) region, which consists of a top Z-shaped meta-atom, a middle dielectric layer, and a bottom VO₂ film. By adjusting structure parameters of VO₂ film, perfect absorption is realized at the frequency of 0.525 THz with the overall absorption beyond 91%. When VO₂ is in insulating state, the top Z-shaped meta-atom will interact with the bottom Z-shaped structure, and the resonance coupling leads to the appearance of electromagnetically induced transparency (EIT). The designed metal-VO₂ hybrid metamaterial opens possible avenues for switchable functionalities in a single device. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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12 pages, 5331 KiB

Open AccessArticle

Investigation of Silver Nanowire Transparent Heated Films Possessing the Application Scenarios for Electrothermal Ceramics

by Yefu Hu and Weimin Wu

Coatings 2023, 13(3), 607; https://doi.org/10.3390/coatings13030607 - 13 Mar 2023

Viewed by 1317

Abstract

As transparent heated films (THFs) based on transparent conductive oxides (TCOs) are restricted by expensive raw materials and inappropriate fabricating film on curved surfaces because of its brittleness, silver nanowires transparent conductive film (AgWS-TCF) is an ideal alternative material for THF. However, there [...] Read more.

As transparent heated films (THFs) based on transparent conductive oxides (TCOs) are restricted by expensive raw materials and inappropriate fabricating film on curved surfaces because of its brittleness, silver nanowires transparent conductive film (AgWS-TCF) is an ideal alternative material for THF. However, there are still many problems to be solved in the electrical and thermal stability of AgNWs-TCF. In this paper, an Al-doped ZnO (AZO) nanoparticles produced by magnetron sputtering was used to modify and coat the AgNWs network, and the ceramic /AgNWs@AZO-TCF was obtained. Compared with ceramic/AgNWs-TCF, the sheet resistance of ceramic/AgNWs@AZO-TCF decreased from 53.2 to 19.3 Ω/sq, resistance non-uniformity decreased from 18.0% to 7.0%, and the inoxidizability, current-impact resistance, and failure voltage increased significantly. In addition, the electrothermal efficiency of ceramic/AgNWs@AZO-TCF is significantly improved after sputtering a SiO₂ layer on the surface of ceramic substrate. Compared with ceramic/AgNWs@AZO-TCF, the temperature of ceramic-SiO₂/AgNWs@AZO-TCF increases from 78.7 to 113.2 °C under applied voltage of 6 V, which possess the application scenarios for electrothermal-ceramics teacup (or tableware) to realize the function of heat preservation and disinfection. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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12 pages, 2492 KiB

Open AccessArticle

Electrochemical and Optical Analysis of Various Compositions of Au and Ag Layers for Blood Cancer Prognosis

by Ulya Farahdina, Amastasia Salsabila Muliawati, Vinda Zakiyatuz Zulfa, Miftakhul Firdhaus, Ihwanul Aziz, Hari Suprihatin, Darsono Darsono, Nasori Nasori and Agus Rubiyanto

Coatings 2023, 13(1), 186; https://doi.org/10.3390/coatings13010186 - 14 Jan 2023

Cited by 1 | Viewed by 1559

Abstract

The fabrication of silver (Ag) and gold (Au) thin film electrodes was successfully carried out using the DC sputtering deposition method. These thin film electrodes were able to detect the increase in serum albumin concentration that was used as a prognostic factor for [...] Read more.

The fabrication of silver (Ag) and gold (Au) thin film electrodes was successfully carried out using the DC sputtering deposition method. These thin film electrodes were able to detect the increase in serum albumin concentration that was used as a prognostic factor for leukemia. The simulation and the optical experimental analysis show that an increase in BSA concentration can increase the absorbance peak observed at a wavelength of 435 nm on hypoalbumin medium and 470 nm on normal concentration of serum albumin medium. The performance of the electrodes was electrochemically tested, in which it was shown that a decrease in oxidation and reduction peaks occurred with respect to an increase in BSA concentration. An oxidation peak was observed at a voltage of 0.5 V for the Ag thin film. For the Au, Au/Ag, and Ag/Au thin films, an oxidation peak was observed at a voltage of 1.0 V. The limits of detection (LODs) of the Ag, Ag/Au, Au, and Au/Ag thin films were 0.56, 0.24, 0.64, and 0.36 g/dL, respectively. Therefore, based on both the electrochemical and optical analysis, the Ag/Au thin film possessed the highest potential for prognosis monitoring of leukemia compared with the other Ag and Au thin films. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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19 pages, 4702 KiB

Open AccessArticle

Influence of Surface Coating towards the Controlled Toxicity of ZnO Nanoparticles In Vitro

by Faruq Mohammad, Ibrahim Birma Bwatanglang, Hamad A. Al-Lohedan, Jilani Purusottapatnam Shaik, Hissah Hamad Al-Tilasi and Ahmed A. Soleiman

Coatings 2023, 13(1), 172; https://doi.org/10.3390/coatings13010172 - 12 Jan 2023

Cited by 7 | Viewed by 2090

Abstract

The uncertainties in ZnO-mediated toxicity and particle stability in a biological system remain a challenge and mitigate against deployment as next-generation nanoparticles (NPs), especially in biomedical applications. With that perspective, the present study investigates the surface chemical properties of ZnO NPs coated with [...] Read more.

The uncertainties in ZnO-mediated toxicity and particle stability in a biological system remain a challenge and mitigate against deployment as next-generation nanoparticles (NPs), especially in biomedical applications. With that perspective, the present study investigates the surface chemical properties of ZnO NPs coated with three different surfactant biomolecules, namely polyethylene glycol (PEG), cetyltrimethylammonium bromide (CTAB), and sodium dodecyl sulfate (SDS) to control the toxicity-induced potentials. On the testing of the surface-functionalized ZnO NPs, notable changes in the particle sizes, morphology, zeta potential, and hydrodynamic size compared to the pure ZnO NPs are observed. In addition, FTIR spectroscopy, TGA, XRD, XPS, and HRTEM analysis showed significant changes in the surface structures and surface functional groups of the three different ZnO NPs on surface functionalization. Following the physical characterization, the cell viability of rat liver BRL-3A-treated ZnO–PEG, ZnO–CTAB, and ZnO–SDS compared to pure ZnO NPs (<50%) falls between 70% and 95% in a dose-determined manner. The cells treated with the pure ZnO NPs showed a higher percentage of apoptotic cells (~61%), which is significantly higher than the 3.4%, 1.5%, and 0.6% for ZnO–PEG-, ZnO–CTAB-, and ZnO–SDS-treated cells (respectively). Furthermore, the surface functionalization was significantly observed to reduce the content of reactive oxygen species (ROS) to 13.6%, 9.7%, and 2.6% compared to the content level of ~71% from the pure ZnO-treated cells. Besides the marked impairment of mitochondrial potentials induced by the pure ZnO NPs, the surfactant–ZnO NPs were observed to slow down the induction of DNA fragmentation and retain the structural integrity of mitochondrial membranes. The toxicity effects are controlled in the order of ZnO–SDS > ZnO–CTAB > ZnO–PEG, i.e., anionic > cationic > non-ionic. Overall from the analysis, the study stresses the importance of having a suitable surface ligand for the ZnO NPs so as to use them in the biomedical sector. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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9 pages, 3594 KiB

Open AccessArticle

Properties of the YbF₃ Films Prepared by Ion-Assisted Deposition

by Peng Sun, Jinlin Bai, Jiahuan He, Ming Yang, Jianzhong Su, Yiqin Ji and Huasong Liu

Coatings 2022, 12(11), 1693; https://doi.org/10.3390/coatings12111693 - 07 Nov 2022

Cited by 1 | Viewed by 1245

Abstract

The purpose of this study is to characterize the microstructure, composition, optical properties and residual stress of YbF₃ films. The films were deposited by ion-assisted deposition at different ion energy. The SEM images showed that the surface of the film was uniform [...] Read more.

The purpose of this study is to characterize the microstructure, composition, optical properties and residual stress of YbF₃ films. The films were deposited by ion-assisted deposition at different ion energy. The SEM images showed that the surface of the film was uniform and smooth. The XRD patterns showed that the YbF₃ films presented an amorphous microstructure. XPS measurement revealed that the ratio of F and Yb reduced with increasing ion energy. The optical constants of the films were determined from the whole optical spectrum. The refractive index increased with the ion energy. Due to the decrease in the amount of F, non-stoichiometric films were formed, and the visible light absorption of the films increased with increasing ion energy. Higher ion energy could increase the packing density, resulting in a decrease in the moisture absorption of the film. The films exhibited tensile stress. The value of residual stress increased with increasing ion energy, since moisture adsorption had an important effect on the residual stress. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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19 pages, 4757 KiB

Open AccessArticle

Influence of Surface Properties and Microbial Growth Media on Antibacterial Action of ZnO

by Dustin Johnson, John M. Reeks, Alexander Caron, Iakovos Tzoka, Iman Ali, Shauna M. McGillivray and Yuri M. Strzhemechny

Coatings 2022, 12(11), 1648; https://doi.org/10.3390/coatings12111648 - 30 Oct 2022

Cited by 2 | Viewed by 1891

Abstract

Nano- and microscale ZnO demonstrate robust antibacterial action, although the driving mechanisms remain undetermined. In this study for commercial ZnO nano-powders and home-grown ZnO microparticles of varying morphologies we probe the response to bacterial growth media in isolation and with Staphylococcus aureus bacteria. [...] Read more.

Nano- and microscale ZnO demonstrate robust antibacterial action, although the driving mechanisms remain undetermined. In this study for commercial ZnO nano-powders and home-grown ZnO microparticles of varying morphologies we probe the response to bacterial growth media in isolation and with Staphylococcus aureus bacteria. ZnO microparticles are synthesized via a controllable hydrothermal method and subjected to biological assays with varying microbial environments. Changes in the optoelectronic, structural and chemical properties of these crystals before and after such exposure are characterized utilizing temperature-dependent photoluminescence spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy. This is done to evaluate the impact of surface-surface interactions in antibacterial assays and the role ZnO surface and morphological properties play in these processes. In our experiments various bacterial environments are employed to elucidate the effects of media interactions on the cytotoxic efficacy of ZnO. In particular, minimum inhibitory concentration assays with Staphylococcus aureus reveal that microscale particles exhibit antibacterial efficacy comparable to that of the nano-powders, indicating that intra-bacterial internalization is not necessary for antimicrobial action. In our studies we determine that the nature of structural and optoelectronic changes in ZnO depends on both the media type and the presence (or absence) of bacteria in these media. Further evidence is provided to support significant cytotoxicity in the absence of particle internalization in bacteria, further highlighting the role of surface and media interactions in this process. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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7 pages, 1385 KiB

Open AccessArticle

Ultra-Low Reflectivity in Visible Band of Vanadium Alumina Nanocomposites

by Qiujin Wang, Guozhong Zhao and Hai Wang

Coatings 2022, 12(9), 1276; https://doi.org/10.3390/coatings12091276 - 01 Sep 2022

Viewed by 1075

Abstract

The high-temperature annealing effect of a V₂O₅/Al₂O₃ bilayer on the reflectivity of visible band was studied in the present work. It was found that the V₂O₅ (200 nm)/Al₂O₃ (30 nm) [...] Read more.

The high-temperature annealing effect of a V₂O₅/Al₂O₃ bilayer on the reflectivity of visible band was studied in the present work. It was found that the V₂O₅ (200 nm)/Al₂O₃ (30 nm) sample (A-0) has a nano-granular surface morphology without a definite crystalline phase. The reflectance of A-0 overreaches 60% as the wavelength is larger than 650 nm, and its minimum reflectance (20%) occurs at the wavelength of ~500 nm. After in situ annealing treatment at 750 °C for 30 min, a triclinic AlVO₄ phase appears while the nano-granular surface morphology remains (sample A-30). The reflectivity of A-30 is well suppressed in comparison with that of A-0 especially in the long wavelength range. Its minimum reflectivity approaches 5% at ~500 nm wavelength. It is speculated that the appearance of a new AlVO₄ nanophase is the main reason for the decline of reflectivity. Extending the annealing time to 60 min, the reflectivity spectrum, as well as the surface morphology, are almost the same. These results can be helpful for applications of vanadium alumina nanocomposites in high-temperature environments. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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13 pages, 3165 KiB

Open AccessFeature PaperArticle

Mid-Infrared HgTe Colloidal Quantum Dots In-Situ Passivated by Iodide

by Zekang Liu, Peng Wang, Ran Dong, Wei Gong, Jingjie Li, Dichao Dai, Hui Yan and Yongzhe Zhang

Coatings 2022, 12(7), 1033; https://doi.org/10.3390/coatings12071033 - 21 Jul 2022

Cited by 2 | Viewed by 1715

Abstract

Today, colloidal quantum dots (CQDs) have received wide attention due to their properties of tunable infrared absorption. For example, HgTe colloidal quantum dots have shown excellent optical absorption (absorption coefficient α > 10⁴ cm⁻¹), spectral absorption tunability covering the entire [...] Read more.

Today, colloidal quantum dots (CQDs) have received wide attention due to their properties of tunable infrared absorption. For example, HgTe colloidal quantum dots have shown excellent optical absorption (absorption coefficient α > 10⁴ cm⁻¹), spectral absorption tunability covering the entire infrared atmospheric window, and even the terahertz (THz). However, the efficient surface passivation of HgTe CQDs was limited by the highly sterically hindered long-chain organic ligands. Here, we demonstrate a new method to synthesize monodisperse mid-infrared HgTe CQDs, and the preparation process of the Hg precursor solution is optimized. With I⁻ in-situ passivated on the surfaces, the spherical HgTe quantum dots are successfully synthesized with the tunability size from 8 to 15 nm. The noise current density of the photoconductive device is as low as 10⁻¹¹ A·Hz^−1/2 at 130 K with a frequency of 1 Hz. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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12 pages, 4659 KiB

Open AccessArticle

Ultrasonic-Assisted Deposition Method for Creating Conductive Wrinkles on PDMS Surfaces

by Juanjuan Wang, Lele Li, Enping Liu, Xue Han and Conghua Lu

Coatings 2022, 12(7), 955; https://doi.org/10.3390/coatings12070955 - 06 Jul 2022

Viewed by 1675

Abstract

Harnessing surface wrinkle surfaces in various functional devices has been a hot topic. However, rapidly creating wrinkled surfaces on elastomers of arbitrary shape (especially curved surfaces) is still a great challenge. In this work, an ultrasonic-assisted deposition method has been proposed to achieve [...] Read more.

Harnessing surface wrinkle surfaces in various functional devices has been a hot topic. However, rapidly creating wrinkled surfaces on elastomers of arbitrary shape (especially curved surfaces) is still a great challenge. In this work, an ultrasonic-assisted deposition method has been proposed to achieve nanomodification of the robust layer (e.g., carbon nanotubes (CNTs)) with a labyrinth wrinkle pattern on polydimethylsiloxane (PDMS) fiber, sheet, and porous sponge. It is found that the swelling effect of the dispersion and the ultrasonic treatment play vital roles in the surface wrinkling. As a demonstration, the conductive wrinkled CNTs@PDMS fibers were assembled as stretchable strain sensors. The initial conductivity and the strain-sensing performances could be well tuned by simply adjusting the ultrasonic treatment time. The wrinkled CNTs@PDMS fiber strain sensor exhibited remarkable stretchability (ca. 300%) and good sensitivity, which can be applied in various human motion detection, voice recognition, and air-flow monitoring. It is also expected that the facile ultrasonic-assisted deposition method for surface wrinkling can be extended to fabricate various smart devices with promoted performances. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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8 pages, 1566 KiB

Open AccessArticle

Reduced Dislocation Density of an InP/GaAs Virtual Substrate Grown by Metalorganic Chemical Vapor Deposition

by Yu-Li Tsai and Chih-Hung Wu

Coatings 2022, 12(6), 723; https://doi.org/10.3390/coatings12060723 - 24 May 2022

Viewed by 1577

Abstract

Integrating indium phosphide (InP) material on a gallium arsenide (GaAs) substrate to form an InP/GaAs virtual substrate has been an attractive research subject over the past decade. However, the epitaxial growth of InP on GaAs is challenging due to a large mismatch in [...] Read more.

Integrating indium phosphide (InP) material on a gallium arsenide (GaAs) substrate to form an InP/GaAs virtual substrate has been an attractive research subject over the past decade. However, the epitaxial growth of InP on GaAs is challenging due to a large mismatch in the lattice constant and thermal expansion coefficient. This paper describes the successful hetero-epitaxy of InP on a GaAs substrate by metalorganic chemical vapor deposition. The hetero-epitaxy in this study utilized a hybrid growth method involving a thin indium gallium arsenide (InGaAs) linearly graded buffer, two-step InP growth, and a post-annealing process. Transmission electron microscopic observations showed that a traditional two-step InP/GaAs virtual substrate was smooth but had a high threading dislocation density (TDD) of 1.5 × 10⁹ cm⁻² near the InP surface. The high TDD value can be reduced to 2.3 × 10⁸ cm⁻² by growing the two-step InP on a thin InGaAs linearly graded buffer. The TDD of an InP/GaAs virtual substrate can be further improved to the value of 1.5 × 10⁷ cm⁻² by removing the low-temperature InP nucleation layer and carrying out a post-annealing process. A possible reason for the improvement in TDD may relate to a dislocation interaction such as the annihilation of mobile threading dislocations. Room-temperature photoluminescence spectra of InP/GaAs virtual substrates with different TDD values were compared in this study. The optical and micro-structural characterization results suggest that the proposed growth method may be feasible for making good-quality and relatively low-cost InP/GaAs virtual substrates for the integration of optoelectronic devices on them. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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13 pages, 30083 KiB

Open AccessArticle

Symmetrically Controlled Design of Twin Alumina-Co Composite Thin Films

by Yunkai Qi, Jianjun Gu, Guochao Shi, Xin Li, Ao Wang and Shumin Yang

Coatings 2022, 12(2), 223; https://doi.org/10.3390/coatings12020223 - 09 Feb 2022

Viewed by 1053

Abstract

Self-assembled dual-working electrode electrolytic cells were designed to produce twin alumina-Co composite films with highly symmetrical microstructures using a deflected electric field-assisted alternating current electrodeposition method. The results show that the deposition current density, microstructure, and optical and magnetic properties of the twin [...] Read more.

Self-assembled dual-working electrode electrolytic cells were designed to produce twin alumina-Co composite films with highly symmetrical microstructures using a deflected electric field-assisted alternating current electrodeposition method. The results show that the deposition current density, microstructure, and optical and magnetic properties of the twin composite films exhibit a high degree of symmetry. The distribution of magnetic Co particles in the alumina nanopores can be changed by adjusting the magnitude of the deflected electric field, resulting in a synchronous symmetrical change in the microstructure of the composite films, which enables the fine-tuning of the magneto-optical properties of the twin alumina-Co composite films at the microscopic scale. The current density distribution on the surface of the twin composite films along the direction of the deflected electric field was quantitatively analyzed by theoretical calculations and numerical simulations. The results show that the deposition current density gradually increases from 0.024 A/m² in region C to 0.056 A/m² in region A at 6 V deflection voltage. The saturation magnetization intensity gradually increases along the radial direction, which is 118, 130, and 150 kA/m, respectively Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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9 pages, 1977 KiB

Open AccessArticle

Structural Color Control of CoFeB-Coated Nanoporous Thin Films

by Xiaomin Zhu, Cuicui Zhao, Weiwei Zhang, Bo Zhang, Mengtao Sun, Xinhua Chen, Vladimir I. Belotelov and Yujun Song

Coatings 2021, 11(9), 1123; https://doi.org/10.3390/coatings11091123 - 16 Sep 2021

Cited by 7 | Viewed by 2128

Abstract

Unlike color dyes, structural colors only slightly fade during long-term usage. Here, structural colors were controllably achieved by constructing CoFeB photonic crystal layers on the surface of a nanoporous aluminum oxide (AAO) substrate by magnetron sputtering deposition. The resulting material showed a wide [...] Read more.

Unlike color dyes, structural colors only slightly fade during long-term usage. Here, structural colors were controllably achieved by constructing CoFeB photonic crystal layers on the surface of a nanoporous aluminum oxide (AAO) substrate by magnetron sputtering deposition. The resulting material showed a wide visible spectral response and achieved structural color control with a high resolution, high color purity, and saturation. The angle-dependent color changes of CoFeB@AAO films were further investigated by changing the incident light angle. The simulation results of the model are consistent with the experiments, which is significant in practical applications. This strategy may have great potential applications for solid structure color coatings, anti-counterfeiting and security, information storage, and electromagnetic sensors. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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15 pages, 4637 KiB

Open AccessArticle

Production and Characterization of Al-Si Coatings Fabricated by Mechanical Alloying Method on Inconel 625 Superalloy Substrates

by Serhan Köktaş, Ali Bülent Önay and Ahmet Çağrı Kılınç

Coatings 2021, 11(9), 1016; https://doi.org/10.3390/coatings11091016 - 25 Aug 2021

Cited by 2 | Viewed by 1928

Abstract

Inconel superalloys are used substantially in high-temperature environments. However, these alloys suffer from corrosion and wear. Attempts to overcome these drawbacks involve coating the metal with different techniques and materials. In this study, a new method with increasing potential was utilized. Using the [...] Read more.

Inconel superalloys are used substantially in high-temperature environments. However, these alloys suffer from corrosion and wear. Attempts to overcome these drawbacks involve coating the metal with different techniques and materials. In this study, a new method with increasing potential was utilized. Using the mechanical alloying process in a planetary ball mill vial, alloying and the Al-Si coatings were concurrently achieved on Inconel 625 substrates. Different process control agent (PCA) ratios, milling ball diameters, and milling times were used to improve coating properties. Macro and microstructure, morphology, microhardness, and roughness values of samples were evaluated and compared. Additionally, crystallographic and cross-sectional properties were investigated in order to optimize the processing conditions. The results indicated that increasing the diameter of the grinding ball enhanced the hardness and thickness of these coatings and increased the roughness values. Longer processing time also enhanced the thickness with mechanical values. However, under these conditions, coating homogeneity decreased, and incompatible regions were formed on the coatings. PCA content brought a refined grain structure, hence showed better mechanical properties. On the other hand, processing time should be increased to get a denser and thicker protective layer against the operational conditions. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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12 pages, 5189 KiB

Open AccessArticle

Thermal Stability of CsPbBr₃ Perovskite Quantum Dots Assembled with SBA-15

by Hongyu Chen, Yunfei Wang, Jianing Wang and Wenyan Liu

Coatings 2021, 11(8), 953; https://doi.org/10.3390/coatings11080953 - 09 Aug 2021

Cited by 8 | Viewed by 4956

Abstract

Nowadays, the excellent performance of metal halide perovskite quantum dots (PQDs) has been demonstrated, but the stability is still a perplexing issue. In this paper, the CsPbBr₃ QDs were assembled into SBA-15 for the first time. The thermal stability and photoluminescence (PL) [...] Read more.

Nowadays, the excellent performance of metal halide perovskite quantum dots (PQDs) has been demonstrated, but the stability is still a perplexing issue. In this paper, the CsPbBr₃ QDs were assembled into SBA-15 for the first time. The thermal stability and photoluminescence (PL) intensity of SBA-15@CsPbBr₃ QDs were improved. The PL spectra of pure CsPbBr₃ QDs have red-shift (~6 nm) with the increasing temperature. However, that of SBA-15@CsPbBr₃ QDs have almost no red-shift. The PL intensity of SBA-15@CsPbBr₃ QDs decreased slightly after heating and cooling for several times. By comparison, the PL intensity of pure CsPbBr₃ QDs decreased more significantly. The experimental results showed that SBA-15 played a significant role in improving the thermal stability of PQDs, which will have an excellent potential for the application of PQDs in the future. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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20 pages, 8550 KiB

Open AccessArticle

Heat Transfer in Nanomaterial Suspension (CuO and Al₂O₃) Using KKL Model

by Muhammad Awais, Saeed Ehsan Awan, Muhammad Asif Zahoor Raja, Muhammad Nawaz, Wasim Ullah Khan, Muhammad Yousaf Malik and Yigang He

Coatings 2021, 11(4), 417; https://doi.org/10.3390/coatings11040417 - 04 Apr 2021

Cited by 21 | Viewed by 2019

Abstract

Novel nonlinear power-law flux models were utilized to model the heat transport phe-nomenon in nano-micropolar fluid over a flexible surface. The nonlinear conservation laws (mass, momentum, energy, mass transport and angular momentum) and KKL cor-relations for nanomaterial under novel flux model were solved [...] Read more.

Novel nonlinear power-law flux models were utilized to model the heat transport phe-nomenon in nano-micropolar fluid over a flexible surface. The nonlinear conservation laws (mass, momentum, energy, mass transport and angular momentum) and KKL cor-relations for nanomaterial under novel flux model were solved numerically. Computed results were used to study the shear-thinning and shear-thickening nature of nano pol-ymer suspension by considering n-diffusion theory. Normalized velocity, temperature and micro-rotation profiles were investigated under the variation of physical parame-ters. Shear stresses at the wall for nanoparticles (CuO and Al₂O₃) were recorded and dis-played in the table. Error analyses for different physical parameters were prepared for various parameters to validate the obtained results. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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Review

Jump to: Research

38 pages, 14607 KiB

Open AccessReview

Bifunctional Electrocatalysts Materials for Non-Aqueous Li–Air Batteries

by Guanghui Yue, Zheyu Hong, Yongji Xia, Tianlun Yang and Yuanhui Wu

Coatings 2022, 12(8), 1227; https://doi.org/10.3390/coatings12081227 - 22 Aug 2022

Cited by 5 | Viewed by 2062

Abstract

Rechargeable lithium–air batteries (LABs), particularly the nonaqueous form, are demonstrated as the next-generation energy conversion and storage equipment for many applications. The air cathode has been certified as one of the critical aspects to affect the full performance of the LABs. At present, [...] Read more.

Rechargeable lithium–air batteries (LABs), particularly the nonaqueous form, are demonstrated as the next-generation energy conversion and storage equipment for many applications. The air cathode has been certified as one of the critical aspects to affect the full performance of the LABs. At present, the main challenge for the commercial application of air cathode is to exploit some new cathode catalysts with lower prices, higher efficiency, and better stability. In the last decade, tremendous efforts have been dedicated to developing new structure design and fabrication processes of the cathode materials to promote the full capability of the LABs. The recent research progress of bifunctional cathode catalysts for LABs, including the main improvement strategies and performance of cathode materials, is introduced in this paper. Besides, related technical challenges are analyzed, and possible resolving strategies for the challenges to develop the nonaqueous Li–air battery catalytic cathodes are elaborated on in this review. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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21 pages, 4858 KiB

Open AccessReview

Recent Advances of Preparation and Application of Two-Dimension van der Waals Heterostructure

by Luhang Song, Moru Song, Zongyu Lu, Gang Yu, Zhan Liang, Wei Hou, Qingwei Liao and Yujun Song

Coatings 2022, 12(8), 1152; https://doi.org/10.3390/coatings12081152 - 09 Aug 2022

Cited by 5 | Viewed by 2785

Abstract

With paramount electrical, optical, catalytic, and other physical and chemical properties, van der Waals heterostructures (vdWHs) have captured increasing attention. vdWHs are two-dimension (2D) heterostructures formed via van der Waals (vdW) force, paving the way for fabricating, understanding, and applications of 2D materials. [...] Read more.

With paramount electrical, optical, catalytic, and other physical and chemical properties, van der Waals heterostructures (vdWHs) have captured increasing attention. vdWHs are two-dimension (2D) heterostructures formed via van der Waals (vdW) force, paving the way for fabricating, understanding, and applications of 2D materials. vdWHs materials of large lattice constant difference can be fabricated together, forming a series of unique 2D materials that cannot form heterostructures earlier. Additionally, vdWHs provide a new platform to study the interlayer interactions between materials, unraveling new physics in the system. Notably, vdWHs embody short-range bonds weaker than covalent and ionic bonds, almost only interactions between nearest particles are considered. Owing to a clear interface, vdW interaction between two different components, devices made by vdWHs can bring amazing physicochemical properties, such as unconventional superconductivity, super capacitance in intercalation 2D structure, etc. Recently, impressive progress has been achieved in the controlled preparation of vdWHs and various applications, which will be summarized in this review. The preparation methods comprise mechanical exfoliation, liquid phase stripping, physical vapor deposition, chemical vapor deposition, and metalorganic chemical vapor deposition. The applications sections will focus on photoelectric devices, logic devices, flexible devices, and piezotronics. Finally, some perspectives in the future on the controlled preparation of vdWHs with desired properties for advanced applications will be discussed. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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26 pages, 10556 KiB

Open AccessReview

Low-Frequency Broadband Absorbing Coatings Based on MOFs: Design, Fabrication, Microstructure and Properties

by Wei Si, Qingwei Liao, Wei Hou, Liyin Chen, Xiaolu Li, Zhiwei Zhang, Minna Sun, Yujun Song and Lei Qin

Coatings 2022, 12(6), 766; https://doi.org/10.3390/coatings12060766 - 02 Jun 2022

Cited by 9 | Viewed by 2648

Abstract

Although most microwave absorbing materials (MAMs) have good absorption ability above 8 GHz, they perform poorly in the low-frequency range (1–8 GHz). Metal–organic frameworks (MOFs) derived carbon-based composites have been highly sought after in electromagnetic materials and functional devices, due to their high [...] Read more.

Although most microwave absorbing materials (MAMs) have good absorption ability above 8 GHz, they perform poorly in the low-frequency range (1–8 GHz). Metal–organic frameworks (MOFs) derived carbon-based composites have been highly sought after in electromagnetic materials and functional devices, due to their high specific area, high porosity, high thermal stability, low reflection loss, and adjustable composition. In this review, we first introduce the three loss types of MAMs and argue that composite materials are effective ways to achieve broadband absorption. Secondly, the absorbing properties of traditional materials and MOF materials in the literature are compared, followed by a discussion of the promising strategies for designing MAMs with broadband absorption in low frequencies based on the recent progress. Finally, the main problems, fabrication methods, and applications are discussed for their future prospects. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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27 pages, 7866 KiB

Open AccessReview

Prospects and Challenges of Flexible Stretchable Electrodes for Electronics

by Wei Hou, Qingwei Liao, Shuang Xie, Yujun Song and Lei Qin

Coatings 2022, 12(5), 558; https://doi.org/10.3390/coatings12050558 - 20 Apr 2022

Cited by 28 | Viewed by 8024

Abstract

The application of flexible electronics in the field of communication has made the transition from rigid physical form to flexible physical form. Flexible electrode technology is the key to the wide application of flexible electronics. However, flexible electrodes will break when large deformation [...] Read more.

The application of flexible electronics in the field of communication has made the transition from rigid physical form to flexible physical form. Flexible electrode technology is the key to the wide application of flexible electronics. However, flexible electrodes will break when large deformation occurs, failing flexible electronics. It restricts the further development of flexible electronic technology. Flexible stretchable electrodes are a hot research topic to solve the problem that flexible electrodes cannot withstand large deformation. Flexible stretchable electrode materials have excellent electrical conductivity, while retaining excellent mechanical properties in case of large deformation. This paper summarizes the research results of flexible stretchable electrodes from three aspects: material, process, and structure, as well as the prospects for future development. Full article

(This article belongs to the Special Issue Advances in Nanostructured Thin Films and Coatings)

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