▎ 摘　　要

Recently, based on the tremendous progresses in performance of perovskite solar cells (PSCs), the inverted planar PSCs have attracted attentions for future applications. Since the traditional poly(3,4-ethylenedioxythiophene) hole transport layer could cause a loss of open-circuit voltage (V-oc), some organic and inorganic alternatives have been widely investigated. However, the V-oc is still below for the demand of optimized value. Here, we demonstrate that the reduced graphene oxide (RGO) doping is a facile and effective method to make molybdenum oxide (MoOx) as a promising hole transport layer (HTL) for high-performance PSCs. The conductive MoOx:RGO HTL can facilitate perovskite crystallization and reduce the potential losses of V-oc in devices. Thus, a high PCE of up to 18.15% is achieved which simultaneously possesses a high V-oc of 1.12 V. With this strategy, the MoOx:RGO provides a novel hole transport layer for high performance and decently stable optoelectronic devices. More importantly, it opens up the research significance of doping in inorganic buffer interlayers for the perovskite solar cells.