▎ 摘　　要

Perovskite photovoltaics have appeared as a promising technology for new-generation photovoltaics. Developing a hole blocking layer (HBL) has also proven to be a successful method of enhancing the efficiency of perovskite solar cells (PSCs). Hereof, planar 3D/2D structured devices are developed using a reduced graphene oxide (rGO) modified tin oxide (SnO2). The results show that the modified HBL can improve perovskite crystallization, optical absorption, and passivate interface trap-defect at the perovskite/SnO2 interface. The modification impact accounts for the improvement of charge transfer and better work function alignment of SnO2. When an optimized 3% rGO additive was incorporated into the SnO2 layer, the PSC exhibited the champion performance in shortcurrent density (Jsc), open-circuit voltage (Voc), and fill factor (FF) of the PSCs, which were 24.11 mA/cm2, 1.093 V, and 79.64%, respectively, and the efficiency was boosted from 16.48% to 20.98%. This HBL modification route allows for defect passivation, which improves the performance of perovskite photovoltaics even more.