B位掺杂(CH_3NH_3)Pb_(0.5)M_(0.5)I_3(M=C,Si,Ge,Sn)环境友好型光电转化材料第一性原理研究

First-principle Investigation of B Sites Doped the Environment-friendly Photoelectric Conversion Material(CH_3NH_3)Pb_(0.5)M_(0.5)I_3(M=C,Si,Ge,Sn)

采用Material Studio(MS)计算软件中的CASTEP软件包构建出环境友好型钙钛矿太阳能电池材料(CH3NH3)Pb0.5M0.5I3(M=C,Si,Ge,Sn)包括母体在内的共计25种位形,研究了B位掺杂对其结构和物理性能的影响.首先,通过GGA+WC关联函数对25种位形分别进行几何优化和能量优化,并获得最终优化后的几何结构与总能量;其次,寻找到能量最低对应的几何结构,并将该结构作为最稳定结构进行研究;计算结果表明,所有位形都属于半导体.随着B位掺杂元素有效离子半径的减小,晶胞体积收缩,带隙有减小的趋势,在费米能级附近态密度分裂成的子带数量逐渐增加,电子密度逐渐降低,光学吸收峰逐渐从高频向低频移动.

Using Materials Studio program based on the first-principles,the environmental-friendly materials（CH3NH3）Pb0.5M0.5I3（M=C,Si,Ge,Sn）has been built.It is useful to investigate how the B sites doping affect the structure and physical properties.Firstly,the 25 kinds of configurations are optimized by GGA＋WC correlation function and the energy corresponding to geometries are obtained.Secondly,by contrast with the total energy for one element substitution,the lowest energy corresponding to the geometry as the most stable structure is found and as targets.The results show that all the configurations are semiconductors.With the decrease of the effective ionic radius of the element at the B site doping,the cell volume shrinks and the band gap decreases,the number of the density of states spliting into sub-bands near theFermi level increases,electron density decreases,and optics absorption peaks gradually move to high frequency from low frequency from high frequency to low frequency.This research provides a new view to prepare the environmentally friendly materials.