Search

ReS2 is a member of the transition metal dichalcogenide family, which has attracted widespread attention in the field of optoelectronics due to its van der Waals interactions between layers, suitable band gap, high optical absorption coefficient and long carrier migration distance. The excellent characteristics of photoelectric materials and devices are determined by their electronic structure, while the defect energy levels of semiconductors have an important role in regulating the electronic structure. However, research on the defects of bulk ReS2 is still lacking. This paper conducts a study on the formation energy and stability of rhenium vacancy, sulfur va- cancy, tungsten-doped (or tungsten replacing) rhenium, tungsten-doped sulfur, technetium - doped rhenium and technetium-doped sulfur in bulk ReS2 based on first-principles calculations using density functional theory. The results indicate that tungsten doped sulfur and technetium doped sulfur form deep acceptor energy level defects, while rhenium vacancy forms shallow acceptor energy level defect. Under conditions of Re rich and S rich, the defect formation energy of tungsten-doped rhenium is low and can effectively reduce the total energy of the system, improving the stability of the system. Although tungsten - doped sulfur defects can reduce the total energy of the system and improve the stability of ReS2, the large defect formation energy indicates that tungsten doped sulfur defects are difficult to form. These research results help to understand the influence of defect energy levels on the shallow and deep energy levels and stability of semiconductors, and also provide theoretical basis for designing efficient photoelectronic devices based on ReS2 in future experiments. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Biochar possesses abundant surface functional groups, which can form stable chemical bonds with nitric oxide (NO) molecules through chemical adsorption, making it inexpensive, readily available, and environmentally adaptable with broad application prospects. However, current research on the adsorption characteristics of NO on biochar surfaces mostly remains at the macroscopic mechanism, lacking in-depth analysis of the underlying microscopic mechanism. In this study, based on density functional theory, this paper investigated the adsorption and transformation pathways of nitric oxide (NO) on biochar surfaces, revealing the adsorption property of biochar towards NO. The results show that the energy of the N-down adsorption configuration is generally lower than that of the O-down adsorption configuration, making it a more probable adsorption structure, with oxygen-containing functional groups playing a crucial role in the NO adsorption and the formation of ammonia (NH3). Furthermore, further analysis of the N-down configuration reveals that NO will preferentially replace hydroxyl groups after binding to active sites, ultimately converting to NH3 on the surface of biochar. Additionally, reaction rates were calculated using the canonical variational transition state theory (CVT), indicating that the pathway favored by NO will be limited by reaction rates in different regions. This study employs quantum chemical methods to comprehensively elucidate the microscopic mechanisms of NO adsorption on biochar surfaces, providing theoretical support for optimizing the application of biochar in NO control. [ABSTRACT FROM AUTHOR]

Nanoparticles with unique structures are widely used in polymer materials. In this paper, the co-assembled phase behavior of three-armed star-shaped AB diblock copolymers and homopolymers blending systems was systematically investigated by using a dissipative particle dynamics model. The morphology of AB/A blends co-assembly was effectively controlled by adjusting the concentration ratio of the star-shaped copolymer in aggregate and the length ratio of the AB block. Some interesting structures were predicted, such as the core-shell-patch structure with a thicker shell layer, the disc-like structure with a depressed centre of the shell layer, and the multicompartmental structure with an irregular ellipsoidal shape. It is also found that for star-shaped chains with long A-block, increasing the concentration of A homopolymer in the aggregates can eliminate the nuclei formed by B-block within the aggregates. For star-shaped chains with short A-block, a small amount of A homopolymers can induce the aggregates to co-assemble into multi-compartmental nanoparticles with long striped nuclei. [ABSTRACT FROM AUTHOR]

In this paper, density functional theory was used to study different loading sites of the bimetal Rh@Ru on g-C3N4, and the stable binding configuration was determined. Furthermore, the reaction mechanism of the NH3BH3hydrogen evolution catalyzed by the catalyst was studied. By comparing the activation energies required for the three paths of the NH3BH3 hydrogen evolution reaction, it is found that the activation energy of the rate-limiting step of path III is lower, while the activation energies required for paths I and II are higher, and the reaction path III is easier to carry out, so path III is the optimal hydrogenation path. Three mechanisms of hydrogen evolution of NH3BH3 catalyzed by double noble metal Rh@Ru-supported g-C3N4 are revealed from a microscopic perspective, hoping to provide theoretical information for the optimization and design of the NH3BH3 hydrogen evolution catalyst. [ABSTRACT FROM AUTHOR]

SiGeSn alloy material is a semiconductor material with great application potential in the field of optoelectronics because of its high carrier mobility, long carrier lifetime, and high thermodynamic stability of its structure. In this paper, the electronic structure and optical properties of intrinsic semiconductor Si96 and five groups of doping models Si92Ge2Sn2、Si88Ge4Sn4、Si84Ge6Sn6、Si80Ge8Sn8、Si76Ge10Sn10 are constructed and calculated by using the generalized gradient approximation GGA+U method based on density functional theory. Through the analysis of the calculation results, it can be seen that the addition of Ge and Sn reduces the band gap width of Si materials, and the transformation from indirect band gap to direct band gap occurs. In addition, the SiGeSn alloy with the highest concentration of Ge and Sn has relatively high formation energy, and its stability is worse than that of the material with low Ge and Sn content. With the increase of Ge and Sn doping concentrations, the electronic density of states（DES） shows more and more obvious hybridization, and the peak value of the density of states is mainly provided by the s orbital of Si atoms. The increase of Ge and Sn concentrations also increases the absorption coefficient of SiGeSn alloy in the visible and near-infrared regions, the reflectivity increases in the visible and above wavelength ranges, and the refractive index decreases, which makes the extinction coefficient curve move to the infrared region and the optical properties change, indicating that suitable optical properties can be obtained by adjusting the Ge and Sn concentrations, which provides a research direction for SiGeSn semiconductors in the application of optoelectronic materials and devices in the infrared region. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Atomic & Molecular Physics (1000-0364) is the property of Journal of Atomic & Molecular Physics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)