A comparative study of one-step and two-step approaches for MAPbI3 perovskite layer and its influence on the performance of mesoscopic perovskite solar cell

The mesoscopic perovskite solar cells (M-PSCs) were synthesized with MAPbI3 perovskite layers as light harvesters, which were grown with one-step and two-step solution process, respectively. A comparative study was performed through the quantitative correlation of resulting device performance and the crystalline quality of perovskite layers. Comparing with the one-step counterpart, a pronounced improvement in the steady-state power conversion efficiencies (PCEs) by 56.86% was achieved with two-step process, which was mainly resulted from the significant enhancement in fill factor (FF) from 48% to 77% without sacrificing the open circuit voltage (Voc) and short circuit current (Jsc). The enhanced FF was attributed to the reduced non-radiative recombination channels due to the better crystalline quality and larger grain size with the two-step processed perovskite layer. Moreover, the superiority of two-step over one-step process was demonstrated with rather good reproducibility.