Inverted CH3NH3PbI3 perovskite solar cells based on solution-processed V2O5 film combined with P3CT salt as hole transport layer

In perovskite solar cells , inorganic hole transport materials have attracted intense attention because of the properties of high chemical stability, hole mobility and low cost. However, most of the inorganic hole conductors exhibit low performance compared with organic hole transport materials. In this study, a facile solution method was developed to prepare a V 2O5 film combined with P3CT-K thus forming a bilayer structure as hole transport layers in inverted CH3NH3PbI3 solar cells. It was found that the hole transport bilayer not only increased the rate of extraction charge but also reduced charge recombination compared with the P3CT-K only based device. As a result, the power conversion efficiency of inverted CH3NH3PbI3 solar cells based on the bilayer was boosted up to the optimal value of 19.7% (average value: 19.0%). Furthermore, the device maintained an efficiency of more than 86% through one-month follow-up, in which the dense and hydrophobic V2O5 film accounted for the improved device stability.