Tuning the A-site cation and X-site anion composition of CH3NH3PbI3 perovskite material for efficient planar perovskite solar cells

Abstract In order to optimize microstructure and improve the photoelectric properties of planar perovskite solar cells (PSCs), the Cs + and SCN − are selected to tune the A-site cation and X-site anion composition of CH 3 NH 3 PbI 3 material with ABX 3 structure, respectively. The effects of Cs + and SCN − addition on the microstructure and photoelectric properties of (CH 3 NH 3 ) 0.9 Cs 0.1 Pb(I 1-x SCN x ) 3 perovskite films and the performance of PSCs have been systematically investigated. The value of “x” corresponding to the amount of SCN − has been optimized. At the optimum amount of 0.05, the (CH 3 NH 3 ) 0.9 Cs 0.1 Pb(I 0.95 SCN 0.05 ) 3 (Cs 0.1 SCN 0.05 ) PSC achieve the champion power conversion efficiency (PCE) of 18.78% and average PCE of 17.66%, being much higher than that of the reference PSCs. The results indicate that the obtained Cs 0.1 SCN 0.05 perovskite film shows the improved microstructure, better local electric properties, the reduced trap density and suppressed charge recombination, resulting in the promoted carrier transfer and improved performance in PSCs.