The effect of MoO3 interlayer on electro-physical characteristics of the perovskite solar cells

Abstract

This report shows that sequentially deposited CuPc and MoOx films are an effective hole-transport layer (HTL) for perovskite solar cells (PSCs). PSCs with only CuPc hole-transport layer have a low power conversion efficiency (PCE) of 3.51%, which mostly due to a poor fill factor (FF) of 29.4%. The incorporation of the MoOx interlayer between the CuPc layer and the anode (Ag) significantly boosted device FF and PCE up to 63.2% and 8.12%, respectively. The analysis of the impedance spectra of PSCs indicates that the MoOx interlayer reduces HTL resistance and increases the recombination resistance at the perovskite/HTL interface, which increases an effective charge carrier lifetime. Moreover, MoOx electric transport properties depends on the stoichiometry of the crystal structure, which can be varied by tuning vacuum level during the thermal sputtering of MoOx layers. PSCs based on the MoOx layer deposited at low vacuum (10−2 Pa) have reached PCE of 8.12% owing to the optimization of the interlayer energy levels and electric transport properties of MoOx films. In this work, we have developed the double hole-transport layer (HTL) for PSCs, which can prevent perovskite degradation on perovskite/HTL interface and hinder a severe charge recombination.