Hysteresis reduction in planar perovskite solar cell with CH3NH3PbI3 absorber by changing the precursor ratio and electron/hole transport layers

Abstract

In this paper, we investigate the hysteresis of planar perovskite solar cells by altering the absorber (CH3NH3PbI3) precursor ratio and electron/hole transport layers (ETL/HTL) and their influence on minority carrier diffusion length and electron/hole flux. Field screening due to ion migration and also minority carriers recombination are the significant causes of hysteresis in the perovskite solar cells. Our simulation results indicate that the lowest hysteresis factor has corresponded to the precursor ratio of 0.80. Despite the lowest hysteresis at this precursor ratio, the electron/hole barrier at the interface of the ETL/HTL is high. To reduce these barriers height, we have presented a structure with minimal hysteresis by changing the HTL and the ETL from Spiro-OMeTAD to Cu2O/TCTA and TiO2 to ZnO, respectively. The developed structure increased the carrier flux balance and enhanced the electron/hole diffusion length. By choosing the appropriate ETL and HTL in different ranges of the precursor ratio from 0.30 to 1.70, we also presented structures with clearly reduced hysteresis factor.