Understanding ion behavior is crucial for advancing the processing of ceramic materials. Given that ion transport predominantly occurs at grain boundaries (GBs) in ceramics, investigating the electronic states in their vicinity is essential. In this study, we perform electronic structure and Born effective charge (BEC) calculations from first principles based on density functional (perturbation) theory, focusing specifically on the Σ5(310)/[001] GB in cubic-ZrO₂. Our results reveal the emergence of acceptor states just above the top of the valence band near the GB region. Furthermore, we observe significant deviations in the BECs of both Zr and O near the GB region compared to those in the bulk. These findings suggest the possibility of peculiar ion behavior near GB regions, particularly under applied electric fields.

There has been increasing attention on carbon nanotubes (CNTs) as a material with suitable characteristics for gas sensors, such as a large specific surface area and the advantage that all constituent elements are located on the surface. CNTs come in various forms, and among them, the (9,4) chirality CNT is reported to demonstrate high performance. However, synthesizing (9,4) CNTs in isolation presents a challenge. Therefore, in this study, we aim to enhance the performance of CNT-based gas sensors by utilizing the (6,5) chirality CNT, which is readily available and commercially sold, and decorating TiO₂ to form a p-n junction. This approach seeks to create a high-performance, easily obtainable CNT-based gas sensor. Experimental results show that the sensor response is maximized when the weight ratio of carbon atoms in the CNT to TiO₂ is 1:100. Additionally, sensors with smaller particle sizes exhibited higher performance. These findings highlight the importance of controlling the particle size and amount of TiO₂ to improve the performance of CNT/TiO₂-based p-n heterojunction gas sensors.

This study aimed to elucidate the effects of Cs adsorption on the structure and physical properties of weathered biotite (WB) using a molten salt method. WB samples with adsorbed Cs were prepared by varying the amount of added CsCl through the molten salt method. The samples were analyzed using X-ray fluorescence, X-ray diffraction, and X-ray absorption fine structure (XAFS). The results showed that the amount of Cs adsorbed increased in proportion to the amount of CsCl added, while the interlayer spacing remained nearly constant, confirming that the layered structure of WB was preserved. Furthermore, XAFS analysis of Si, a major component of WB’s framework, revealed changes in the electronic structure around Si due to Cs adsorption. These findings indicate that Cs adsorption alters the electronic structure of Si in WB, suggesting the potential for developing novel materials based on the unique properties of WB.

Hydrogen boride nanosheets (HB sheets), which are readily and reliably synthesized experimentally, have attracted attention as hydrogen storage materials. In this study, we performed density functional theory calculations of the HB sheets containing atomic vacancies to evaluate their hydrogen storage performance via hydrogen adsorption. Our results indicate that the adsorption of hydrogen molecules is enhanced by the introduction of a boron vacancy into the structure. Additionally, we re-evaluated the adsorption of a hydrogen molecule on the lithium-decorated HB sheet reported in a previous study, by employing a different set of computational parameters. Furthermore, by analyzing the electronic states, we discussed the underlying adsorption mechanisms. These findings indicate that structural modification alone could improve the hydrogen storage performance of the HB sheet.

Amorphous carbon (a-C) thin films are attractive materials for a wide range of applications. On the other hand, further modification of its surface can impart new features while retaining bulk characteristics. Surface modification of glassy carbon and graphite by electrochemical methods have been widely studied. However, there are relatively few reports on the surface modification of a-C thin films by electrochemical methods. The purpose of this study is to establish a method for the surface modification of a-C thin films with 4-aminobenzoic acid (4-ABA) by electrochemical oxidation and the characterization of the resulting 4-ABA-modified a-C thin films. The surface modification was performed by cyclic voltammetry (CV) in 10 mmol dm⁻³ phosphate buffer containing 4-ABA, using the a-C thin film deposited via pulsed laser deposition as a working electrode. The resulting surfaces have been studied by X-ray photoelectron spectroscopy (XPS) and atomic force microscopy scratching. The XPS N 1s spectrum of the modified a-C surface revealed a peak at a binding energy of 399.5 eV which showed the formation of a carbon-nitrogen bond between the amino cation radical and carbon atom of the a-C thin film surface. The thickness of the modified layer formed by a single-cycle CV in a 1.0 mmol dm⁻³ solution of 4-ABA exceeded the molecular length of 4-ABA, indicating the formation of a multilayer of 4-ABA on the a-C surface.

In the field of materials science, aluminum nitride (AlN) materials have great application potential in key fields, such as optoelectronic devices and high-frequency electronic devices, due to their unique optoelectronic properties. However, it is difficult to obtain the parameters related to its optoelectronic properties, and traditional measurement methods have low precision and poor efficiency. This study aims to solve this problem by constructing an attention-based deep neural network model to perform parameter inversion with high precision and efficiency. An experiment was conducted by employing a dataset comprising the optoelectronic properties of AlN materials, covering different preparation processes and crystal structure states, and the results were compared with an improved physical model (Model 1), a model based on statistical learning (Model 2), and a model based on traditional neural networks (Model 3). The results show that the deep learning model with attention has a significant advantage in terms of the measurement error rate, and the error rate of the light absorption coefficient is only 3.2%, which is much lower than that of Model 1 (12.5%), Model 2 (10.8%), and Model 3 (8.6%). In terms of the measurement efficiency, when the light absorption coefficient is measured as an example, the number of effective measurements per unit time can reach 50, which is far greater than that of the other models. This study provides a new way to measure the optoelectronic parameters of AlN materials and is expected to promote the development of related industries.

The single-source thermal vacuum evaporation (SSTVE) approach was adopted in this study to obtain inorganic perovskite thin films. The structural, morphological, compositional, and photoluminescent properties of the obtained layers were comprehensively investigated. X-ray diffraction analysis confirmed a microcrystalline structure with predominant CsPbBr₃ and Cs₄PbBr₆ phases. Scanning electron microscopy images revealed a uniform polycrystalline morphology with crystallite sizes suitable for optoelectronic applications. Energy-dispersive X-ray spectroscopy indicated a Cs-rich composition, which was attributed to the differences in precursor vaporization behavior. The synthesized films exhibited strong photoluminescence with a distinct emission peak corresponding to the bandgap energy, confirming their potential as photoactive layers for light-emitting diodes. The SSTVE method provides a solvent-free, scalable route for fabricating high-quality inorganic perovskite films, suitable for industrial optoelectronic device manufacturing.

Liquid-crystalline (LC) nitroxide radicals (NRs) with spin 1/2, localized in each mesogen core, exhibit anisotropic paramagnetic susceptibility in their LC phases. It is unclear whether the macroscopic magnetic structures of LC materials depend on the molecular orientational structures in the LC phases. Here, we report the persistence diagram of the macroscopic magnetic structures of an LC-NR on a ferromagnetic iron film in an image taken using photoemission electron microscopy. Furthermore, we discuss the topological aspect of the magnetic structures in the LC-NR by comparing the persistence diagram with that of the molecular orientational structures in a polarized optical micrograph of the same sample.

The Cambridge sequential total energy package (CASTEP) is a first-principles code based on density functional theory, which has been used for calculating spectra of soft X-ray absorption spectroscopy, for example. A post-processing code, OptaDOS, was recently developed, which can calculate the density of states (DOS) and soft X-ray emission spectroscopy (XES) spectra of materials. In this study, we investigate a methodology to calculate the XES of light element materials within the scope of the conventional CASTEP code without using OptaDOS. We investigated two pseudopotential approaches, with and without a core-hole effect and we compared the results with the measured spectra. We found that the simulation without a core-hole effect showed a better agreement with the experiment among the other calculation conditions. In addition, the method successfully deconvoluted the contributions of σ and π orbital components to XES spectra from the takeoff-angle dependent measurement of oriented samples, such as graphite and hexagonal boron nitride. Our study shows that the spectral shape and energy distribution of the π orbital component can also be accurately reproduced using this methodology.