空位有序双钙钛矿A2BX6的弹性和热电性质的第一性原理研究  

Elastic and Thermoelectric Properties of Vacancy Ordered Double Perovskites A2BX6:A DFT Study

作　　者：Muhammad Faizan 赵国琪 张天旭 王啸宇 贺欣[1] 张立军 Muhammad Faizan;Guoqi Zhao;Tianxu Zhang;Xiaoyu Wang;Xin He;Lijun Zhang(College of Materials Science and Engineering,Jilin University,Changchun 130012,China.)

机构地区：[1]吉林大学材料科学与工程学院,长春130012

出　　处：《物理化学学报》2024年第1期46-47,共2页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金(62004080)资助项目。

摘　　要：卤化物钙钛矿在热电应用中表现出了巨大的潜力。准确了解卤化物钙钛矿的热电传输性质对于进一步提高热电设备的应用效率至关重要。本研究采用了Perdew-Burke-Ernzerhof(PBE)和修正的Becke Johnson(mBJ)交换关联泛函探究了卤化物双钙钛矿Rb_(2)SnI6、Rb_(2)PdI6和Cs_(2)PtI6的弹性和热电性质。通过对这些材料的力学稳定性、有效质量、塞贝克系数、功率因子和热电品质因数的研究,我们发现,这三种化合物都是力学稳定的,并且具有可塑性。这些化合物是窄带隙半导体,具有简并的带边结构,结合低的载流子有效质量使得它们具有热电应用潜力。Cs_(2)PtI6在空穴掺杂在500 K温度下可以达到0.76 mV·K^(−1)的高塞贝克系数。由于高塞贝克系数和最大功率因子,Rb_(2)SnI6、Rb_(2)PdI6和Cs_(2)PtI6在p型掺杂下具有高的热电品质因数,分别为0.91、0.96和0.98。总体而言,我们的研究为卤化物钙钛矿的热电性能提供了新的见解,为这些化合物的实验合成提供了有价值的参考。The increasing global demand for energy and the detrimental effects of using fossil fuels highlight the urgent need for alternative and sustainable energy sources.Metal halide perovskites have gained significant research attention over the last few years,primarily for solar energy storage,light emission,and thermoelectrics,due to their low cost and high efficiency.To understand the thermoelectric transport characteristics of halide perovskites and improve their practical applications,precise knowledge of their heat transport mechanism is necessary.In this study,we used density functional theory(DFT)and different exchange-correlation functionals,namely the Perdew-Burke-Ernzerhof(PBE)and modified Becke Johnson(mBJ)schemes,to screen three inorganic halide perovskites,Rb_(2)SnI6,Rb_(2)PdI6,and Cs_(2)PtI6,in their pristine forms for thermoelectric energy conversion.Here,we report the mechanical stability,effective masses,Seebeck coefficient,power factor,and thermoelectric figure of merit.Both PBE and mBJ functionals successfully determined the most stable geometry and accurate electronic structure for each halide perovskite.Initially,we optimized the crystal structures of all three compounds using the PBE functional and obtained the corresponding lattice parameters.The optimized lattice constants are in good agreement with the experimental values.We are the first to calculate the elastic constants and other mechanical parameters,such as the elastic moduli,Poisson’s ratio,Pugh index,elastic anisotropy,and Grüneisen parameter,to determine the elastic and mechanical stability of these compounds.All three compounds(Rb_(2)SnI6,Rb_(2)PdI6,and Cs_(2)PtI6)are mechanically stable and ductile.The effective mass of the electrons at the conduction band minimum was smaller than that of the holes at the valence band maximum.Electronic band structure calculations showed that all three compounds are narrow band gap semiconductors(with band gaps ranging from 0.47 to 1.22 eV)with degenerate band extrema.The low effective masses and

关 键 词：电子结构 有效质量 SEEBECK系数 热电品质因数 卤化物双钙钛矿 

分 类 号：O649[理学—物理化学]