Investigation of effect of doping in perovskite solar cells: A numerical simulation approach

Abstract

In n -i-p structure perovskite solar cells, TiO 2 is a widely used thermally stable and low-cost electron transport layer. But in CsSnI 3 based perovskite solar cells, the undoped-TiO 2 electron transport layer does not provide proper band alignment for efficient charge transportation. The use of doped semiconductors in heterojunction solar cells has improved device performance significantly by shifting the energy levels of the electron and hole transport layers. We have investigated the effect of doping density in the absorber layer, electron transport layer, and hole transport layer on the performance of a device with an FTO/TiO 2 /CsSnI 3 /CuSCN/Au configuration. It is found that the doping density of the electron transport layer (TiO 2 ) and absorber layer (CsSnI 3 ) has a significant effect on the band alignment and thus on the device performance; however, an increase in the acceptor doping density of the hole transport layer (CuSCN) does not make any significant changes in the device performance. In addition, we have optimized the variable parameters of different layers. The optimized device shows an efficiency >25%. These results could help to optimize the performance of CsSnI 3 based n -i-p structure perovskite solar cells with TiO 2 electron transport layer.