双钙钛矿A_(2)SnBr_(6)(A=K,Rb,Cs)电子结构和光学性质的第一性原理研究

First Principles study on the Electronic Structure and Optical Properties of double perovskite A_(2)SnBr_(6)(A=K,Rb,Cs)

近年来,钙钛矿已成为新能源材料科学领域最活跃的材料。本文利用密度泛函理论和广义梯度近似(GGA)研究了A_(2)SnBr_(6)(A=K,Rb,Cs)的结构和光电性质。改进的杂化泛函(HSE06)也用于计算材料的光电特性。结果表明,A2SnBr6钙钛矿的能带结构在G-G方向上具有直接带隙的半导体行为,可以通过改变阳离子的种类对带隙的宽度进行调整。从光学的角度来看,A位阳离子种类的变化对光学的一系列性质影响较小,具有强吸收和低反射。因此,这些化合物是适合光伏应用的光吸收材料。

In recent years,perovskite has become the most active material in the field of new energy materials science.The structure and photoelectric properties of A_(2)SnBr_(6)(A=K,Rb,Cs)are investigated by means of density functional theory and generalized gradient approximation(GGA).The improved Heyd-Scuseria-Ernzerhof(HSE06)hybrid functional is also used to calculate the photoelectric properties of materials.The results show that the band structure of A2SnBr6 perovskite has a direct band gap semiconductor behavior in the G-G direction,and the band gap width can be adjusted by changing the type of cations.From the optical point of view,the change of the type of cations at A-site has little effect on A series of optical properties,with strong absorption and low reflection.Therefore,these compounds are suitable light absorbing materials for photovoltaic applications.