Light emission from multiple self-trapped excitons in one-dimensional Ag-based ternary halides

Ternary metal halides based on Cu(I)and Ag(I)have attracted intensive attention in optoelectronic applications due to their excellent luminescent properties,low toxicity,and robust stability.While the self-trapped excitons(STEs)emission mechanisms of Cu(I)halides are well understood,the STEs in Ag(I)halides remain less thoroughly explored.This study explores the STE emission efficiency within the A_(2)AgX_(3)(A=Rb,Cs;X=Cl,Br,I)system by identifying three distinct STE states in each material and calculating their configuration coordinate diagrams.We find that the STE emission efficiency in this system is mainly determined by STE stability and influenced by self-trapping and quenching barriers.Moreover,we investigate the impact of structural compactness on emission efficiency and find that the excessive electron–phonon coupling in this system can be reduced by increasing the structural compactness.The atomic packing factor is identified as a low-cost and effective descriptor for predicting STE emission efficiency in both Cs_(2)AgX_(3) and Rb_(2)AgX_(3) systems.These findings can deepen our understanding of STE behavior in metal halide materials and offer valuable insights for the design of efficient STE luminescent materials.The datasets presented in this paper are openly available in Science Data Bank at https://doi.org/10.57760/sciencedb.12094.

Joint target assignment and power allocation in the netted C-MIMO radar when tracking multi-targets in the presence of self-defense blanket jamming

The netted radar system(NRS)has been proved to possess unique advantages in anti-jamming and improving target tracking performance.Effective resource management can greatly ensure the combat capability of the NRS.In this paper,based on the netted collocated multiple input multiple output(CMIMO)radar,an effective joint target assignment and power allocation(JTAPA)strategy for tracking multi-targets under self-defense blanket jamming is proposed.An architecture based on the distributed fusion is used in the radar network to estimate target state parameters.By deriving the predicted conditional Cramer-Rao lower bound(PC-CRLB)based on the obtained state estimation information,the objective function is formulated.To maximize the worst case tracking accuracy,the proposed JTAPA strategy implements an online target assignment and power allocation of all active nodes,subject to some resource constraints.Since the formulated JTAPA is non-convex,we propose an efficient two-step solution strategy.In terms of the simulation results,the proposed algorithm can effectively improve tracking performance in the worst case.

High-throughput computational material screening of the cycloalkane-based two-dimensional Dion–Jacobson halide perovskites for optoelectronics

Two-dimensional(2D) layered perovskites have emerged as potential alternates to traditional three-dimensional(3D)analogs to solve the stability issue of perovskite solar cells. In recent years, many efforts have been spent on manipulating the interlayer organic spacing cation to improve the photovoltaic properties of Dion–Jacobson(DJ) perovskites. In this work, a serious of cycloalkane(CA) molecules were selected as the organic spacing cation in 2D DJ perovskites, which can widely manipulate the optoelectronic properties of the DJ perovskites. The underlying relationship between the CA interlayer molecules and the crystal structures, thermodynamic stabilities, and electronic properties of 58 DJ perovskites has been investigated by using automatic high-throughput workflow cooperated with density-functional(DFT) calculations.We found that these CA-based DJ perovskites are all thermodynamic stable. The sizes of the cycloalkane molecules can influence the degree of inorganic framework distortion and further tune the bandgaps with a wide range of 0.9–2.1 eV.These findings indicate the cycloalkane molecules are suitable as spacing cation in 2D DJ perovskites and provide a useful guidance in designing novel 2D DJ perovskites for optoelectronic applications.

Yolk shell-structured pyrite-type cobalt sulfide grafted by nitrogen-doped carbon-needles with enhanced electrical conductivity for oxygen electrocatalysis

Pyrite-type sulfides(PTS)exhibit promising intrinsic activities for oxygen reduction and evolution reactions(ORR/OER).However,their poor electrical conductivities may limit the charge transfer rate to inevitably lower activity.Here,yolk-shell structured cobalt-pyrite nanospheres(CoS_(2)YSS)are prepared and modified with amino groups as nucleation sites for coupling highly-conductive needle-like nitrogendoped carbon via a facile solvothermal method(CoS_(2)YSS@NC).The as-marked CoS_(2)YSS@NC-0.5 shows a gap between yolk and shell,and an obvious exterior layer of grafted NC,which can provide an integrated structure,an interior place,and three exposed surfaces on CoS_(2).CoS_(2)YSS@NC-0.5 reveals higher ORR activity(half-wave potential of 0.88 V)and methanol resistance than commercial Pt/C.Due to in-situ formation of highly-active CoOOH,CoS_(2)YSS@NC-0.5 shows a better overpotential(244 mV at 10 mA/cm^(2))and Tafel slope(135 mV/dec)than RuO2.Zinc-air battery with CoS_(2)YSS@NC-0.5 air-cathode exhibits good open circuit potential(1.44 V),specific capacity(772.5 mAh/g)and cycling stability.Needle-like NC layer coated on the yolk-shell structure of CoS_(2)effectively lowers the charge transfer resistance to obtain extraordinary ORR/OER activities.It indicates that the integration of highly-conductive carbon onto pyritetype sulfides is an effective strategy to acquire durable bifunctional ORR/OER catalysts.

光电半导体材料的理论设计

光电半导体作为一种可以将光能和电能相互转换的材料,近几十年来,在能源和电子信息等领域得到广泛应用.随着计算机算力的提升和理论算法的发展,理论设计方法可以在短时间内探索成百上千种材料,相比于采用试错法的实验方式,具有开发周期短且成本低等特点,逐渐成为新材料研发的关键步骤.通过将物理原则与高通量计算、智能优化算法和机器学习等理论设计策略相结合,可以准确高效地探索性能优异的光电半导体材料.本文概述了光电半导体材料的设计策略和研究进展.首先,介绍基于第一性原理计算光电性质的方法,并分析相关物理性质的成因及其在光电半导体设计方面的意义;然后,结合具体的研究成果对高通量材料筛选、物理原则导向的材料设计、基于智能算法的材料搜索和基于机器学习方法的材料发现等不同的光电半导体设计策略进行概述,为该领域的理论设计方向提供指导原则;最后,对光电半导体设计方面的工作进行总结,并对该领域未来的发展进行展望.

JAMIP:an artificial-intelligence aided data-driven infrastructure for computational materials informatics

Materials informatics has emerged as a promisingly new paradigm for accelerating materials discovery and design.It exploits the intelligent power of machine learning methods in massive materials data from experiments or simulations to seek new materials,functionality,and principles,etc.Developing specialized facilities to generate,collect,manage,learn,and mine large-scale materials data is crucial to materials informatics.We herein developed an artificial-intelligence-aided data-driven infrastructure named Jilin Artificial-intelligence aided Materials-design Integrated Package(JAMIP),which is an open-source Python framework to meet the research requirements of computational materials informatics.It is integrated by materials production factory,high-throughput first-principles calculations engine,automatic tasks submission and monitoring progress,data extraction,management and storage system,and artificial intelligence machine learning based data mining functions.We have integrated specific features such as an inorganic crystal structure prototype database to facilitate high-throughput calculations and essential modules associated with machine learning studies of functional materials.We demonstrated how our developed code is useful in exploring materials informatics of optoelectronic semiconductors by taking halide perovskites as typical case.By obeying the principles of automation,extensibility,reliability,and intelligence,the JAMIP code is a promisingly powerful tool contributing to the fast-growing field of computational materials informatics.

Acid-Stable CoWO_(4)/WO_(3)-Microrod Coated by a Thin Carbon-Layer as Efficient Pt Co-Catalysts for Methanol Oxidation and Oxygen Reduction

Insufficient activity and instability(poisoning)of Pt-based electrocatalysts for methanol oxidation and oxygen reduction reactions(MOR/ORR)impede the development of direct methanol fuel cells.Here,CoWO_(4) nanoparticles-loaded WO_(3) microrods coated by a thin carbon-layer are used as Pt-supports/co-catalysts for MOR/ORR.WO_(3) grows along the(110)crystal plane to form microrod(diameter of~0.6 um),which is coated by a carbon-layer(~5 nm).Pt-CoWO_(4)/WO_(3)@NCL-mr(850℃)shows a higher mass activity(2208 mA mg^(-1)_(pt))than the commercial Pt/C(659.4 mA mg^(-1)_(pt)).CoWO_(4)/WO_(3) heterojunction on the microrod surface with abundant oxygen vacancies allows the generation of surface-adsorbed hydroxyl to facilitate CO elimination and regeneration of the occupied Pt active-sites(promising stability).PtCo WO_(4)/WO_(3)@NCL-mr(850℃)has higher half-wave(0.46 V)and onset(0.54 V)potentials than Pt/C(0.41 and 0.50 V)for ORR.The microrod structure of Co WO_(4)/WO_(3)@NCL facilitates the dispersibility of Pt NPs to increase the utilization of Pt active sites and relieve the self-aggregation of Pt to obtain a promising synergy between Pt and CoWO_(4)(Co^(2+))for ORR in acid media.This study provides insights not only into the synthesis of acid-resistant WO_(3)@NCL microrod as active Pt co-catalyst,but also into the effective utilization of surface oxygen vacancies and Co^(2+) for MOR/ORR.

Helium incorporation induced direct-gap silicides

The search of direct-gap Si-based semiconductors is of great interest due to the potential application in many technologically relevant fields.This work examines the incorporation of He as a possible route to form a direct band gap in Si.Structure predictions and first-principles calculations show that He and Si,at high pressure,form four dynamically stable phases of Si_(2)He(oP36-Si_(2)He,tP9-Si_(2)He,mC18-Si_(2)He,and mC12-Si_(2)He).All phases adopt host–guest structures consisting of a channel-like Si host framework filled with He guest atoms.The Si frameworks in oP36-Si2He,tP9-Si2He,and mC12-Si_(2)He could be retained to ambient pressure after removal of He,forming three pure Si allotropes.Among them,oP36-Si_(2)He and mC12-Si_(2)He exhibit direct band gaps of 1.24 and 1.34 eV,respectively,close to the optimal value(~1.3 eV)for solar cell applications.Analysis shows that mC12-Si_(2)He with an electric dipole transition allowed band gap possesses higher absorption capacity than cubic diamond Si,which makes it to be a promising candidate material for thin-film solar cell.