Special Issue "Inorganic Materials in Nanotechnology: Fabrication, Characterization and Application"

A special issue of Nanomaterials (ISSN 2079-4991). This special issue belongs to the section "Inorganic Materials and Metal-Organic Frameworks".

Deadline for manuscript submissions: 8 March 2023 | Viewed by 11153

Special Issue Editor

Dr. Akinobu Yamaguchi
E-Mail Website
Guest Editor
Laboratory of Advanced Science and Technology for Industry, University of Hyogo, Kobe, Japan
Interests: heterostructure; superlattice; multilayer; nanotechnology; synthesis; fabrication; characterization; application; catalysis; inorganic materials

Special Issue Information

Dear Colleagues,

The tailored properties of nano/microscale structured inorganic materials have become a very active field. Heterojunctions such as metal/metal and oxide/metal interfaces are of great importance in a wide range of applications. For example, metallic multilayers prompted the discovery of the giant magnetoresistive (GMR) effect just as the semiconductor superlattice structure created lasers and radiofrequency devices. The GMR effect is derived from spin-dependent scattering, which occurs even at room temperature, resulting in the application of magnetic recording to hard disk drives progressing and supporting current cloud systems. The oxide/metal heterojunction is developed toward the discovery of the coherent tunneling magnetoresitive (TMR) effect. These studies related to spintronics have attracted much attention for both the understanding of fundamental magnetic/electric interaction and engineering applications such as magnetic random access memory (MRAM), microwave oscillators, and the integration of a system that imitates a neural circuit.

Depending on surface terminating species, the work function is known to be modulated near the interface, whereas in some cases, it also affects bulk properties. Therefore, that is, if this control is performed, the band structure can also be modulated. Consequently, it can be developed into functional materials and element structures such as artificial multiferroic material and spintronic devices.

This Special Issue aims to cover experimental and/or theoretical studies including materials informatics, in the field of synthesis, fabrication, and characterization of nano/micromaterials. Advanced synthesis and fabrication processes, characterizations, and activity/stability evaluation of inorganic materials are very welcome. Manuscripts on research and development related to electric state, chemical state control, and heterostructure introduction, including not only basic research but also applied research are also welcome. We are also looking for research papers to conduct physical property research under desirable experimental conditions by creating ideal experimental systems such as those used in spintronics, molecular electronics, and lab-on-a-chip.

Dr. Akinobu Yamaguchi
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Nanomaterials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (12 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Research

Article
Advances in Laser Additive Manufacturing of Cobalt–Chromium Alloy Multi-Layer Mesoscopic Analytical Modelling with Experimental Correlations: From Micro-Dendrite Grains to Bulk Objects
Nanomaterials 2022, 12(5), 802; https://doi.org/10.3390/nano12050802 - 26 Feb 2022
Cited by 1 | Viewed by 850
Abstract
This study presents two analytical models for the laser powder bed fusion (LPBF) process. To begin, the single layer’s dimensions were measured using principal operating conditions, including laser power, laser scanning speed, powder layer thickness, and hatch distance. The single-layer printing dimensions were [...] Read more.
This study presents two analytical models for the laser powder bed fusion (LPBF) process. To begin, the single layer’s dimensions were measured using principal operating conditions, including laser power, laser scanning speed, powder layer thickness, and hatch distance. The single-layer printing dimensions were transformed into multi-layer printing using the hatch distance. The thermal history of the printed layers was used as an input to the Johnson–Mehl–Avrami-Kolmogorov model to estimate the average dendrite grain size. LPBF experiments were conducted for a Cobalt–chromium (Co–Cr) alloy to validate the developed model. The average dendrite grain size was estimated using a scanning electron microscope (SEM) combined with “Image J” software. The Vickers hardness test was performed to correlate the average dendrite grain size and operating conditions. A 10–15% mean absolute deviation was presented between experiments and simulation results. In all samples, a Co-based γ-FCC structure was identified. An inverse correlation was established between the laser power and smaller average dendrite grain, while a direct relationship has been determined between laser scanning speed and average dendrite grain size. A similar trend was identified between hatch distance and average dendrite grain size. A direct link has been determined between the average dendrite grain size and hardness value. Furthermore, a direct relationship has connected the laser volume energy density and hardness value. This study will help experimentalists to design operating conditions based on the required grain size and corresponding mechanical characteristics. Full article
Show Figures

Figure 1

Article
Characterization of Silver Nanowire-Based Transparent Electrodes Obtained Using Different Drying Methods
Nanomaterials 2022, 12(3), 461; https://doi.org/10.3390/nano12030461 - 28 Jan 2022
Viewed by 829
Abstract
Metal-based transparent top electrodes allow electronic devices to achieve transparency, thereby expanding their application range. Silver nanowire (AgNW)-based transparent electrodes can function as transparent top electrodes, owing to their excellent conductivity and transmittance. However, they require a high-temperature drying process, which damages the [...] Read more.
Metal-based transparent top electrodes allow electronic devices to achieve transparency, thereby expanding their application range. Silver nanowire (AgNW)-based transparent electrodes can function as transparent top electrodes, owing to their excellent conductivity and transmittance. However, they require a high-temperature drying process, which damages the bottom functional layers. Here, we fabricated two types of AgNW-based electrodes using the following three drying methods: thermal, room-temperature, and vacuum. Thereafter, we investigated the variation in their morphological, electrical, and optical characteristics as a function of the drying method and duration. When the AgNW-exposed electrode was dried at room temperature, it exhibited a high surface roughness and low conductivity, owing to the slow solvent evaporation. However, under vacuum, it exhibited a similar electrical conductivity to that achieved by thermal drying because of the decreased solvent boiling point and fast solvent evaporation. Conversely, the AgNW-embedded electrodes exhibited similar roughness values and electrical conductivities regardless of the drying method applied. This was because the polymer shrinkage during the AgNW embedding process generated capillary force and improved the interconnectivity between the nanowires. The AgNW-based electrodes exhibited similar optical properties regardless of the drying method and electrode type. This study reveals that vacuum drying can afford transparent top electrodes without damaging functional layers. Full article
Show Figures

Graphical abstract

Article
The Effect of Silane Coupling Agent on the Texture and Properties of In Situ Synthesized PI/SiO2 Nanocomposite Film
Nanomaterials 2022, 12(2), 286; https://doi.org/10.3390/nano12020286 - 17 Jan 2022
Viewed by 398
Abstract
PI/SiO2 composite films have been prepared by using in situ polymerization. The influences of the dosage of silane coupling agent (KH-560) on the structure and performance of PI/SiO2 composite film have been investigated. The results show that in the components without [...] Read more.
PI/SiO2 composite films have been prepared by using in situ polymerization. The influences of the dosage of silane coupling agent (KH-560) on the structure and performance of PI/SiO2 composite film have been investigated. The results show that in the components without KH-560, the addition of SiO2 decreases the transmittance of the sample. Compared to the same SiO2 doping amount, the transmittance in the visible light range of the sample using KH-560 is higher than that of the sample without KH-560. After adding KH-560, the tensile strength, the elastic modulus the elongation at break of the sample have largely changed. The thermal stability and the ability to resist ultraviolet radiation of the composite film first increases and then decreases. Furthermore, the optimal dosage of KH-560 is 3%. Moreover, the addition of KH-560 has little effect on the transmittance of the PI/SiO2 composite films before and after UV irradiation. Full article
Show Figures

Figure 1

Article
Growth Mechanism of Periodic-Structured MoS2 by Transmission Electron Microscopy
Nanomaterials 2022, 12(1), 135; https://doi.org/10.3390/nano12010135 - 31 Dec 2021
Cited by 4 | Viewed by 646
Abstract
Molybdenum disulfide (MoS2) was grown on a laser-processed periodic-hole sapphire substrate through chemical vapor deposition. The main purpose was to investigate the mechanism of MoS2 growth in substrate with a periodic structure. By controlling the amount and position of the [...] Read more.
Molybdenum disulfide (MoS2) was grown on a laser-processed periodic-hole sapphire substrate through chemical vapor deposition. The main purpose was to investigate the mechanism of MoS2 growth in substrate with a periodic structure. By controlling the amount and position of the precursor, adjusting the growth temperature and time, and setting the flow rate of argon gas, MoS2 grew in the region of the periodic holes. A series of various growth layer analyses of MoS2 were then confirmed by Raman spectroscopy, photoluminescence spectroscopy, and atomic force microscopy. Finally, the growth mechanism was studied by transmission electron microscopy (TEM). The experimental results show that in the appropriate environment, MoS2 can be successfully grown on substrate with periodic holes, and the number of growth layers can be determined through measurements. By observing the growth mechanism, composition analysis, and selected area electron diffraction diagram by TEM, we comprehensively understand the growth phenomenon. The results of this research can serve as a reference for the large-scale periodic growth of MoS2. The production of periodic structures by laser drilling is advantageous, as it is relatively simpler than other methods. Full article
Show Figures

Figure 1

Article
Anisotropy of 3D Columnar Coatings in Mid-Infrared Spectral Range
Nanomaterials 2021, 11(12), 3247; https://doi.org/10.3390/nano11123247 - 29 Nov 2021
Cited by 1 | Viewed by 845
Abstract
Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70 to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared [...] Read more.
Polarisation analysis in the mid-infrared fingerprint region was carried out on thin (∼1 μm) Si and SiO2 films evaporated via glancing angle deposition (GLAD) method at 70 to the normal. Synchrotron-based infrared microspectroscopic measurements were carried out on the Infrared Microspectroscopy (IRM) beamline at Australian Synchrotron. Specific absorption bands, particularly Si-O-Si stretching vibration, was found to follow the angular dependence of ∼cos2θ, consistent with the absorption anisotropy. This unexpected anisotropy stems from the enhanced absorption in nano-crevices, which have orientation following the cos2θ angular dependence as revealed by Fourier transforming the image of the surface of 3D columnar films and numerical modeling of light field enhancement by sub-wavelength nano-crevices. Full article
Show Figures

Figure 1

Article
Nano/Micro-Structured ZnO Rods Synthesized by Thermal Chemical Vapor Deposition with Perpendicular Configuration
Nanomaterials 2021, 11(10), 2518; https://doi.org/10.3390/nano11102518 - 27 Sep 2021
Cited by 1 | Viewed by 551
Abstract
Under a one-step process, catalyst-free growth of one-dimensional (1D) ZnO hierarchical nanostructures was performed on ZnO-seeded Si substrate by thermal chemical vapor deposition with a perpendicular setup. The morphological and crystallographic properties of the nano/micro-structured ZnO rods were investigated with varying growth temperature [...] Read more.
Under a one-step process, catalyst-free growth of one-dimensional (1D) ZnO hierarchical nanostructures was performed on ZnO-seeded Si substrate by thermal chemical vapor deposition with a perpendicular setup. The morphological and crystallographic properties of the nano/micro-structured ZnO rods were investigated with varying growth temperature and growth time. X-ray diffraction patterns of 1D ZnO double-structured rods showed the hexagonal wurtzite structure. The morphology and crystal structure of the ZnO double-structured rods were sensitive to the growth temperature and growth time. From Raman scattering and photoluminescence spectra, the orientation and size effects of the ZnO double-structured rods were discussed in relation to growth temperatures and growth times. Full article
Show Figures

Figure 1

Article
Using Gold-Nanorod-Filled Mesoporous Silica Nanobeads for Enhanced Radiotherapy of Oral Squamous Carcinoma
Nanomaterials 2021, 11(9), 2235; https://doi.org/10.3390/nano11092235 - 30 Aug 2021
Cited by 2 | Viewed by 1086
Abstract
Radiotherapy (RT), in combination with surgery, is an essential treatment strategy for oral cancer. Although irradiation provides effective control over tumor growth, the surrounding normal tissues are almost inevitably affected. With further understanding of the molecular mechanisms involved in radiation response and recent [...] Read more.
Radiotherapy (RT), in combination with surgery, is an essential treatment strategy for oral cancer. Although irradiation provides effective control over tumor growth, the surrounding normal tissues are almost inevitably affected. With further understanding of the molecular mechanisms involved in radiation response and recent advances in nanotechnology, using gold nanoparticles as a radiosensitizer provides the preferential sensitization of tumor cells to radiation and minimizes normal tissue damage. Herein, we developed gold nano-sesame-beads (GNSbs), a gold-nanorod-seeded mesoporous silica nanoparticle, as a novel radioenhancer to achieve radiotherapy with a higher therapeutic index. GNSbs in combination with 2 Gy irradiation effectively enhanced the cytotoxic activity CAL-27 cells. The well-designed structure of GNSbs showed preferential cellular uptake by CAL-27 cells at 24 h after incubation. Gold nanorods with high density modified on mesoporous silica nanoparticles resulted in significant reactive oxygen species (ROS) formation after irradiation exposure compared with irradiation alone. Furthermore, GNSbs and irradiation induced more prominent DNA double-strand breaks and G2/M phase arrest in CAL-27 than those in L929. In animal studies, radiotherapy using GNSbs as a radiosensitizer showed significant suppression of tumor growth in an orthotopic model of oral cancer. These results demonstrate that using GNSbs as a radiosensitizer could possess clinical potential for the treatment of oral squamous carcinoma. Full article
Show Figures

Figure 1

Article
Microstructure Evaluation and Impurities in La Containing Silicon Oxynitrides
Nanomaterials 2021, 11(8), 1896; https://doi.org/10.3390/nano11081896 - 23 Jul 2021
Cited by 1 | Viewed by 819
Abstract
Oxynitride glasses are not yet commercialised primarily due to the impurities present in the network of these glasses. In this work, we investigated the microstructure and instinctive defects in nitrogen rich La−Si−O−N glasses. Glasses were prepared by heating a powder mixture of pure [...] Read more.
Oxynitride glasses are not yet commercialised primarily due to the impurities present in the network of these glasses. In this work, we investigated the microstructure and instinctive defects in nitrogen rich La−Si−O−N glasses. Glasses were prepared by heating a powder mixture of pure La metal, Si3N4, and SiO2 in a nitrogen atmosphere at 1650–1800 °C. The microstructure and impurities in the glasses were examined by optical microscopy, scanning electron microscopy, atomic force microscopy, and transmission electron microscopy in conjunction with electron energy-loss spectroscopy. Analyses showed that the glasses contain a small amount of spherical metal silicide particles, mostly amorphous or poorly crystalline, and having sizes typically ranging from 1 µm and less. The amount of silicide was estimated to be less than 2 vol. %. There was no systematic relation between silicide formation and glass composition or preparation temperature. The microstructure examination revealed that the opacity of these nitrogen rich glasses is due to the elemental Si arise from the decomposition reaction of silicon nitride and silicon oxide, at a high temperature above ~1600 °C and from the metallic silicide particles formed by the reduction of silicon oxide and silicon nitride at an early stage of reaction to form a silicide intermetallic with the La metal. Full article
Show Figures

Figure 1

Article
Bimetallic ZIF-Derived Co/N-Codoped Porous Carbon Supported Ruthenium Catalysts for Highly Efficient Hydrogen Evolution Reaction
Nanomaterials 2021, 11(5), 1228; https://doi.org/10.3390/nano11051228 - 06 May 2021
Cited by 2 | Viewed by 1199
Abstract
Exploring the economical, powerful, and durable electrocatalysts for hydrogen evolution reaction (HER) is highly required for practical application. Herein, nanoclusters-decorated ruthenium, cobalt nanoparticles, and nitrogen codoped porous carbon ([email protected]) are prepared with bimetallic zeolite imidazole frameworks (ZnCo-ZIF) as the precursor. Thus, the prepared [...] Read more.
Exploring the economical, powerful, and durable electrocatalysts for hydrogen evolution reaction (HER) is highly required for practical application. Herein, nanoclusters-decorated ruthenium, cobalt nanoparticles, and nitrogen codoped porous carbon ([email protected]) are prepared with bimetallic zeolite imidazole frameworks (ZnCo-ZIF) as the precursor. Thus, the prepared [email protected] catalyst with a low Ru loading of 3.13 wt% exhibits impressive HER catalytic behavior in 1 M KOH, with an overpotential of only 30 mV at the current density of 10 mA cm−2, Tafel slope as low as 32.1 mV dec−1, and superior stability for long-time running with a commercial 20 wt% Pt/C. The excellent electrocatalytic properties are primarily by virtue of the highly specific surface area and porosity of carbon support, uniformly dispersed Ru active species, and rapid reaction kinetics of the interaction between Ru and O. Full article
Show Figures

Figure 1

Article
X-ray Photoemission Spectroscopy Study of Uniaxial Magnetic Anisotropy Induced in a Ni Layer Deposited on a LiNbO3 Substrate
Nanomaterials 2021, 11(4), 1024; https://doi.org/10.3390/nano11041024 - 16 Apr 2021
Viewed by 795
Abstract
The competition between magnetic shape anisotropy and the induced uniaxial magnetic anisotropy in the heterojunction between a ferromagnetic layer and a ferroelectric substrate serves to control magnetic domain structures as well as magnetization reversal characteristics. The uniaxial magnetic anisotropy, originating from the symmetry [...] Read more.
The competition between magnetic shape anisotropy and the induced uniaxial magnetic anisotropy in the heterojunction between a ferromagnetic layer and a ferroelectric substrate serves to control magnetic domain structures as well as magnetization reversal characteristics. The uniaxial magnetic anisotropy, originating from the symmetry breaking effect in the heterojunction, plays a significant role in modifying the characteristics of magnetization dynamics. Magnetoelastic phenomena are known to generate uniaxial magnetic anisotropy; however, the interfacial electronic states that may contribute to the uniaxial magnetic anisotropy have not yet been adequately investigated. Here, we report experimental evidence concerning the binding energy change in the ferromagnetic layer/ferroelectric substrate heterojunction using X-ray photoemission spectroscopy. The binding energy shifts, corresponding to the chemical shifts, reveal the binding states near the interface. Our results shed light on the origin of the uniaxial magnetic anisotropy induced from the heterojunction. This knowledge can provide a means for the simultaneous control of magnetism, mechanics, and electronics in a nano/microsystem consisting of ferromagnetic/ferroelectric materials. Full article
Show Figures

Figure 1

Article
Nano-Magnetic NiFe2O4 and Its Photocatalytic Oxidation of Vanillyl Alcohol—Synthesis, Characterization, and Application in the Valorization of Lignin
Nanomaterials 2021, 11(4), 1010; https://doi.org/10.3390/nano11041010 - 15 Apr 2021
Cited by 3 | Viewed by 1300
Abstract
Here, we report on a phyto-mediated bimetallic (NiFe2O4) preparation using a Boswellia carterii extract, which was characterized by XRD, FT-IR, TGA, electron microscopy, magnetic spectroscopy, and Mössbauer spectroscopy measurements. The prepared nano-catalysts were tested for oxidation of lignin monomer [...] Read more.
Here, we report on a phyto-mediated bimetallic (NiFe2O4) preparation using a Boswellia carterii extract, which was characterized by XRD, FT-IR, TGA, electron microscopy, magnetic spectroscopy, and Mössbauer spectroscopy measurements. The prepared nano-catalysts were tested for oxidation of lignin monomer molecules—vanillyl alcohol and cinnamyl alcohol. In comparison with previously reported methods, the nano NiFe2O4 catalysts showed high photocatalytic activity and selectivity, under visible light irradiation with a nitroxy radical initiator (2,2,6,6-tetramethylpiperidinyloxy or 2,2,6,6-tetramethylpiperidine 1-oxyl; TEMPO) at room temperature and aerobic conditions. The multifold advantages of the catalyst both in terms of reduced catalyst loading and ambient temperature conditions were manifested by higher conversion of the starting material. Full article
Show Figures

Figure 1

Article
Sonochemical Synthesis, Characterization and Optical Properties of Tb-Doped CdSe Nanoparticles: Synergistic Effect between Photocatalysis and Sonocatalysis
Nanomaterials 2021, 11(2), 378; https://doi.org/10.3390/nano11020378 - 02 Feb 2021
Cited by 2 | Viewed by 786
Abstract
In this study, Tb-doped CdSe nanoparticles with variable Tb3+ content were synthesized by a simple sonochemical technique. The synthesized nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD). The sono-photocatalytic activities of the as-prepared [...] Read more.
In this study, Tb-doped CdSe nanoparticles with variable Tb3+ content were synthesized by a simple sonochemical technique. The synthesized nanoparticles were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD). The sono-photocatalytic activities of the as-prepared specimens were assessed for the degradation of Reactive Black 5. The experimental results show that the sono-photocatalytic process (85.25%) produced a higher degradation percentage than the individual sono- (22%) and photocatalytic degradation (8%) processes for an initial dye concentration and Tb-doped CdSe dosage of 20 mg/L and 1 g/L, respectively. Response surface methodology (RSM) was utilized to assess model and optimize the impacts of the operational parameters, namely, the Tb3+ content, initial dye concentration, catalyst dosage, and time. The addition of benzoquinone results in remarkably inhibited degradation and the addition of ammonium oxalate reduced the removal percentage to 24%. Superoxide radicals and photogenerated holes were detected as the main oxidative species. Full article
Show Figures

Figure 1

Back to TopTop