Enhanced charge collection with ultrathin AlOx electron blocking layer for hole-transporting material-free perovskite solar cell

Abstract

An ultrathin AlO_x layer has been deposited onto a CH₃NH₃PbI₃ film using atomic layer deposition technology, to construct a metal–insulator–semiconductor (MIS) back contact for the hole-transporting material-free perovskite solar cell. By optimization of the ALD deposition cycles, the average power conversion efficiency (PCE) of the cell has been enhanced from 8.61% to 10.07% with a highest PCE of 11.10%. It is revealed that the improvement in cell performance with this MIS back contact is mainly attributed to the enhancement in charge collection resulting from the electron blocking effect of the AlO_x layer.