无机非铅钙钛矿CsBBr_(3)(B=Sn,Ge,Si,C)电子和光学性质的第一性原理计算

First-principles Study on the Electronic Structure and Optical Property of Inorganic Lead-free Perovskite CsBBr_(3)(B=Sn,Ge,Si,C)

利用第一性原理对CsBBr_(3)(B=Sn,Ge,Si,C)的能带结构、电子态密度和吸收谱进行了系统的计算.结果显示:CsSnBr_(3)、CsGeBr_(3)、CsSiBr_(3)和CsCBr_(3)均属于p型直接带隙半导体,价带主要由Br-4p轨道贡献,导带主要由Sn-5p、Ge-4p、Si-3p或C-2p轨道形成,其中CsCBr_(3)在波长300~900 nm范围内具有更高的吸收系数,平均吸收系数大约是CsPbBr_(3)的3倍.

The band structure,electron state density,and absorption spectrum of CsBBr_(3)(B=Sn,Ge,Si,C)were calculated systematically by using first-principles.The results showed that CsSnBr_(3),CsGeBr_(3),CsSiBr_(3) and CsCBr_(3) were p-type direct bandgap semiconductors,the valence band was mainly contributed by Br-4p orbital,and the conduction band was mainly formed by Sn-5p,Ge-4p,Si-3p or C-2p orbital.CsCBr_(3) has a higher absorption coefficient in the wavelength range of 300 to 900 nm,and the average absorption coefficient is about 3 times of that of CsPbBr_(3).