Ferroelectric semiconductors, with their inherent spontaneous polarization, present a promising approach for efficient charge separation, making them attractive for photovoltaic applications. The potential of β-AgGaO2, a polar ternary oxide with an orthorhombic Pna21 structure, as a light-absorbing material is evaluated. First-principles computational analysis reveals that β-AgGaO2 possesses an indirect bandgap of 2.1 eV and exhibits pronounced absorption within the visible spectral range. Optical simulations suggest that a 300 nm thick absorber layer could theoretically achieve a power conversion efficiency (PCE) of 20%. Device-level simulations using SCAPS-1D evaluate the influence of hole and electron transport layers on solar cell performance. Among the tested hole transport materials, Cu2FeSnS4 (CFTS) achieves the highest PCE of 14%, attributed to its optimized valence band alignment and reduced recombination losses. In contrast, no significant improvements were observed with the electron transport layers tested. These findings indicate the potential of β-AgGaO2 as a ferroelectric photovoltaic absorber and emphasize the importance of band alignment and interface engineering for optimizing device performance.

As renewable energy technologies advance, identifying efficient photocatalytic materials for water splitting to produce hydrogen has become an important research focus in materials science. This study presents a multi-task regression model (MTRM) designed to predict the conduction band minimum (CBM), valence band maximum (VBM), and solar-to-hydrogen efficiency (STH) of inorganic materials. Utilizing crystallographic and band gap data from over 15,000 materials in the SNUMAT database, machine-learning methods are applied to predict CBM and VBM, which are subsequently used as additional features to estimate STH. A deep neural network framework with a multi-branch, multi-task regression structure is employed to address the issue of error propagation in traditional cascading models by enabling feature sharing and joint optimization of the tasks. The calculated results show that, while traditional tree-based models perform well in single-task predictions, MTRM achieves superior performance in the multi-task setting, particularly for STH prediction, with an MSE of 0.0001 and an R2 of 0.8265, significantly outperforming cascading approaches. This research provides a new approach to predicting photocatalytic material performance and demonstrates the potential of multi-task learning in materials science.

Ferroelectric oxides with large band gaps or band edge positions that are difficult to cross the water oxidation-reduction potential are not conducive to photocatalytic hydrogen production. This study systematically investigates the potential application of R3c-structured InVO3 in the field of photocatalysis through density functional theory calculations. The mechanical and phonon frequency stability of InVO3 is verified through stability analysis, followed by the confirmation of its excellent ferroelectric properties through first-principles calculations. The calculated optical properties of InVO3 are explored to reveal its strong absorption of visible light and high photoelectric conversion efficiency. InVO3 exhibits excellent charge carrier transport properties through calculations of electron mobility, promising efficient energy conversion in photocatalytic water splitting. The band edge positions of InVO3 can cross the water oxidation-reduction potential, providing theoretical support for its application in the field of photocatalysis. R3c-structured InVO3 is a potential high-performance ferroelectric photocatalytic material.

Photocatalytic hydrogen production represents a sustainable and eco-friendly approach to energy generation. Employing Density Functional Theory (DFT) as the analytical framework, the study demonstrates that wurtzite-structured Zn2VN3 exhibits exceptional ferroelectric polarization, significantly surpassing that of conventional ferroelectric materials. Additionally, Zn2VN3 is characterized by enhanced carrier mobility, a critical attribute for augmenting photocatalytic efficiency. Of particular note is the advantageous alignment of Zn2VN3's band edge positions for visible light photocatalysis, coupled with a high solar-to-hydrogen (STH) efficiency, thereby positioning it as a formidable candidate for hydrogen production. The synthesis of a Zn2VN3@MoS2 heterojunction structure is shown to substantially enhance its photocatalytic properties, as evidenced by significant improvements in the hydrogen evolution reaction (HER) performance. Overall, this meticulous analysis positions Zn2VN3 as a material of considerable potential, poised to advance optoelectronic technology and contribute significantly to efficient and sustainable photocatalytic hydrogen production endeavors.

Traditional ferroelectric perovskite oxides are often limited by their wide band gaps, which restrict their efficient use of visible light. Pna21-LaWN3, an innovative perovskite nitride featuring a polar structure, has been investigated for its electronic structure, ferroelectric properties, and photovoltaic performance through Density Functional Theory (DFT) analysis. Our calculations reveal that Pna21-LaWN3 exhibits promising ferroelectric properties, primarily driven by the interaction between W and N atoms. Notably, Pna21-LaWN3 possesses a direct bandgap around 1.3 eV, coupled with a high absorption coefficient, making it highly efficient in absorbing visible light. SLME (Spectroscopic Limited Maximum Efficiency) analysis indicates that Pna21-LaWN3 can achieve significant short-circuit current, with a photoelectric conversion efficiency nearing 32%, thus emerging as an outstanding candidate for ferroelectric photovoltaic applications. The study underscores the potential of Pna21-LaWN3 in overcoming the limitations of traditional ferroelectric materials and paves the way for its use in high-efficiency solar energy harvesting.

Traditional ferroelectric perovskite oxides are often limited by their wide band gaps, which restrict their efficient use of visible light. Pna21-LaWN3, an innovative perovskite nitride featuring a polar structure, has been investigated for its electronic structure, ferroelectric properties, and photovoltaic performance through Density Functional Theory (DFT) analysis. Our calculations reveal that Pna21-LaWN3 exhibits promising ferroelectric properties, primarily driven by the interaction between W and N atoms. Notably, Pna21-LaWN3 possesses a direct bandgap around 1.3 eV, coupled with a high absorption coefficient, making it highly efficient in absorbing visible light. SLME (Spectroscopic Limited Maximum Efficiency) analysis indicates that Pna21-LaWN3 can achieve significant short-circuit current, with a photoelectric conversion efficiency nearing 32 %, thus emerging as an outstanding candidate for ferroelectric photovoltaic applications. The study underscores the potential of Pna21LaWN3 in overcoming the limitations of traditional ferroelectric materials and paves the way for its use in highefficiency solar energy harvesting.

Although nitride materials hold great functional promise, ferroelectric photovoltaic nitrides remain relatively rare within the scientific community. In this study, high-throughput calculations have been employed to explore and predict novel stable ternary nitrides characterized by both high photoelectric conversion efficiency and robust ferroelectric polarization. Notable candidates, including Mg2CrN3, Mg2MnN3, MgVN2, ZnVN2, and X2BiN3 (where X represents Mg, Ca, and Sr), are anticipated to exhibit remarkable ferroelectric photovoltaic properties, with a particular emphasis on efficiently harnessing visible light. The incorporation of early 3d transition metals and bismuth (Bi) elements within ternary metal nitrides is highlighted as a key strategy for achieving high ferroelectric photovoltaic efficiency. Furthermore, these ferroelectric nitrides demonstrate relatively high carrier mobilities, which are conducive to facilitating the transport of photogenerated carriers driven by ferroelectricity. This research offers a selection of promising ternary nitride candidates with substantial potential for application in the field of ferroelectric photovoltaics.

Graphene was predicted to have a long spin relaxation time in the range of microseconds to milliseconds due to its weak spin-orbit coupling and hyperfine interaction. However, very short spin relaxation times were measured experimentally on the order of nanoseconds. Magnetic proximity effect from spin valves were considered strongly to influence the electronic and spin properties in graphene. Here, a graphene/nonmagnetic semiconductor CdX heterostructure is proposed to eliminate the magnetic effect and to fulfill optical injection of spin polarization. Based on the first-principles calculation within the density functional theory, we perform a systematic study on the structural, electronic properties and band structures of the heterostructures, and find that graphene on CdX (X = S, Se and Te) slabs preserves its linear Dirac band structure within the bandgap of CdX, and a built-in electric field occurs near the interface. The built-in electric field drives spin polarized electrons into graphene preferably. An optical detection scheme of spin relaxation time of graphene is proposed based on Faraday and Hanle effects.

Most ferroelectric oxides exhibit relatively wide bandgaps, which pose limitations on their suitability for photovoltaics application. CuNbO3 possesses potential ferroelectric properties with an R3c polar structure that facilitate the separation of charge carriers under illumination, promoting the generation of photovoltaic effects. The optical and ferroelectric properties of R3c-CuNbO3, as well as the effect of strain on the properties are investigated by first-principles calculation in this paper. The calculated results indicate that R3c-CuNbO3 possesses a moderate band gap to absorb visible light. The interaction of Cu-O and Nb-O bonds is considered to have a crucial role in the photovoltaic properties of CuNbO3, contributing to the efficient absorption of visible light. The bandgap of CuNbO3 becomes smaller and the density of states near the conduction and valence bands becomes relatively uniform in distribution under compressive conditions, which improves the photoelectric conversion efficiency to 29.9% under conditions of bulk absorption saturation. The ferroelectric properties of CuNbO3 are driven by the Nb-O bond interactions, which are not significantly weakened by the compressive strain. CuNbO3 is expected to be an excellent ferroelectric photovoltaic material by modulation of compressive strain due to the stronger visible light absorption and excellent ferroelectric behavior.

为适应国家新能源锂电池产业发展的需要,地方高校锂电池实验室作为该专业学生进行实践教学活动的重要场所,在培养学生实践能力和创新精神上具有重要作用.本文对锂电池实验室在管理中面临的主要问题作了阐述,并提出了相应的对策,为地方高校锂电池实验室安全管理和实验室建设提供参考.

The polarization electric field generated by the dipole moment can swiftly separate photogenerated carriers. Herein, the first‐principles calculations to study the structural, electronic, polarization electric field, optical, and photocatalytic properties of 2D polar monolayer silicon monochalcogenide SiX (X = S, Se) are studied. The polarization electric field induced by a noncentrosymmetric structure is a direction from the X (X = S, Se) atomic surface to the Si atomic surface. The polar monolayer SiS (SiSe) is an indirect semiconductor with a bandgap of 2.997 eV (2.903 eV). The absorption coefficients of the polar monolayer SiX (X = S, Se) reach the order of 10 5 cm −1 , and the absorption onset can be extended to the visible light region. The band alignment of the 2D polar monolayer SiX (X = S, Se) is suitable for photocatalytic water splitting. The obtained results show that the 2D polar monolayer SiX (X = S, Se) with a polarization electric field is a potential catalyst for photocatalytic water splitting.

Ferroelectric oxides with large bandgaps have restricted applications in photovoltaic and photocatalytic fields. Based on recent experiments with the ferroelectric compound, LiSbO3, the stability and optoelectronic properties of a new ferroelectric compound, namely Li2SbBiO6, are investigated in this study. The calculated results demonstrate that Li2SbBiO6 satisfies the stability conditions of the elastic coefficients and phonon dynamics. Li2SbBiO6 maintains the ferroelectric polarization strength of LiSbO3 and significantly reduces the bandgap, and thus has been explored for applications in photovoltaic and photocatalytic fields. Li2SbBiO6 is a new potential ferroelectric oxide for harvesting visible light owing to its suitable bandgap and a large hole-electron effective mass ratio.

The double perovskite multiferroic materials Bi2FeCrO6 have a more remarkable improvement in magnetoelectricity, photovoltaic, and photocatalysis performance than BiFeO3. The novel double perovskite multiferroic materials In2FeX (X = V, Cr, Mn, Co, and Ni) O6 are designed to achieve superior performance (e.g., in ferroelectricity and magnetism photovoltaic and photocatalysis) by density functional theory. The calculation results show that In2FeXO6 (X = V or Cr) O6 could be metastable multiferroic material with high ferroelectric polarization strength, and the ferroelectricity is driven by In-O ions interaction. In2FeVO6 has a suitable bandgap and produces high photoelectric conversion efficiency as excellent ferroelectric photovoltaic materials. In2FeVO6 also absorbs visible light to drive water splitting to produce hydrogen under tensile strain by analyzing the band edge position. These calculation results could guide realizing considerable ferroelectric polarization strength, high photovoltaic performance, and photocatalytic hydrolysis hydrogen production.

Polarized structure oxides have unique advantages in photovoltaic field with internal electric field, but it is difficult to make full use of them with visible light in general due to their large band gap. The stability and electronic structure properties of a novel R3c polarization structure MgSnX3 (X=O, S and Se) have been calculated by first-principles method. The calculated results show that the elastic coefficients and phonon frequencies of R3c-MgSnX3 (X=O, S and Se) satisfy the mechanical stability conditions. R3c-MgSnX3 (S and Se) maintains a higher theoretical ferroelectric polarization strength than R3c-MgSnO3, and at the same time reduces the band gap obviously. Spectroscopic Limited Maximum Efficiency calculation also shows that MgSnS3 has high photoelectric conversion efficiency and is a potential ferroelectric photovoltaic material with high efficiency. (C) 2021 Elsevier B.V. All rights reserved.

Polarized structured nitride semiconductors are attractive due to their unique and environment-friendly electronic properties. The stability, ferroelectricity and photocatalytic and photovoltaic properties of super-wurtzite Mg2XN3 (X = Bi, Mo, Nb, Sb, Ta, Tc and W) were determined based on first principles calculations in this study. The calculated results indicate that Mg2XN3 (X = Sb, Ta, Bi and Nb) are stable polar nitrides by phonon frequencies, elastic coefficients and ferroelectric analysis. Mg2XN3 (X = Sb, Ta and Nb) with large ferroelectric polarization strength could absorb ultraviolet light to promote photocatalytic water splitting for hydrogen production. Mg2BiN3 is a new excellent photovoltaic candidate due to its ideal energy band, high electron mobility, high absorption coefficient and large ferroelectric polarization strength.

Materials with high ferroelectric polarization strength and sufficient absorption of visible light have unique advantages in photocatalysis. Based on the results of structure search, phonon frequency, and elasticity coefficient calculations, CaBiO3 has a stable R3 polar structure. First-principles calculations indicate that R3-CaBiO3 is a potentially efficient ferroelectric visible-light photocatalytic material for hydrogen production. CaBiO3 under slight strain can maintain high ferroelectric polarization strength, strong visible light absorption capacity and small effective mass. CaBiO3 under tensile strain has potentially ferroelectric photogeneration of hydrogen with a band edge position that crosses the redox potential of water. These results can expand the application of Bi-based materials in photocatalytic hydrogen production.

高校课程思政与思政课程同向同行,已成为高校教育教学改革的共识.结合"光电子技术"专业课程的特点,挖掘该课程所蕴含的优质思政教育资源,融入到课程教学目标、教学内容、教学方法的设计及教学全过程,以实现专业知识技能培养和人生价值塑造协同并进.

根据实验上合成LiNbO3(LN)构型的ZnTiO3铁电化合物,基于第一性原理的方法设计研究了化合物LN-ZnTiS3(LN构型)的特性.计算结果表明LN-ZnTiS3化合物满足力学稳定条件.根据化学势平衡相图分析,LN-ZnTiS3在常压下不会形成稳定结构,但施加外部压力可以形成稳定结构.电子态密度和带隙的计算结果表明,LN-ZnTiS3的价带顶(VBM)主要由S-p轨道组成,导带底(CBM)则由Ti-d轨道组成,硫原子的替代可以促进体系费米能级以上的电子状态大幅度下降到较低的能级,从而减小LN-ZnTiS3的带隙.LN-ZnTiS3的带隙计算值为1.04 eV,可以促进可见光的吸收,可以看出LN-ZnTiS3是一种潜在的高效率光伏材料.

基于密度泛函理论计算了水分子在二维TiOBr2表面吸附的稳定性,电荷转移和能带的性质.比较了水分子在二维TiOBr2的top位,bridge位和top使的吸附能.计算结果表明水分子吸附在二维TiOBr2表面的hollow位较为稳定,但是吸附能较小为物理吸附.二维TiOBr2表面的Br原子电荷向水分子的氧原子转移.能带计算结果表明水分子并没有在单层TiOBr2引起明显的杂质能级.

The stability, ferroelectricity, and electronic structure of R3c-MgSnO3 and R3c-MgSnO3 under compressive strain were investigated by density functional theory. The calculated phonon frequencies and elastic coefficient indicated that MgSnO3 and MgSnO3 under compressive strain could meet dynamic and mechanical stability. The phonon frequencies, elastic coefficient, and mechanical property have been increased in MgSnO3 under compressive strain, which is explained by the bond length, Bader charge, and electronic structure. The bandgap of R3c-MgSnO3 under compressive strain has been increased to 3.8 eV with an indirect bandgap to enhance optical transparency, which agrees with the experiment. The ferroelectric stability and polarization strength could also be promoted by the compressive strain in MgSnO3. The stability, ferroelectric, mechanical, and photoelectric properties of R3c-MgSnO3 could be controlled by compressive strain.