Abstract Optimizing the underlayer used as an active layer in perovskite solar cells is important for improving their cell performance. We previously demonstrated the usefulness of a rubrene/pentacene bilayer as an underlayer in CH3NH3PbI3 (MAPbI3) cells prepared by alternative vapor deposition of PbI2 and CH3NH3I (MAI). In the present work, to examine the applicability of this rubrene/pentacene bilayer for the deposition of MAPbI3 via a new method involving immersing a PbI2 evaporated film into an MAI solution is used to prepare MAPbI3 films; this method is referred to as a two-step method. Adjustment of the parameters of the two-step method used to prepare MAPbI3 films on rubrene/pentacene bilayers led to cells with a higher power conversion efficiency compared with that of cells with MAPbI3 films deposited directly onto poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), without rubrene/pentacene bilayers. The rubrene/pentacene presumably promotes the suppression of recombination at the interface between MAPbI3 and hole transport layer.
Read full abstract