Dead-bolt type design for efficient and stable perovskite solar cells

Due to the existence of recombination centers and mismatch energy levels, the electrical performance loss at the interface of perovskite solar cells (PSCs) seriously affects the power conversion efficiency (PCE). Here, we presented a dead-bolt type design for efficient and stable perovskite solar cells. MAI and PEAI (MAI@PEAI) double organic salts were sequentially deposited between perovskite and hole transport layer (HTL). The results show that MAI can react with the residual lead iodide (PbI2) on the perovskite surface and form an in situ passivation layer, which can tailor the band structure and enhance charge carrier extraction. PEAI was coated on the in situ passivation layer to further passivate the surface defects. As a result, the dead-bolt type design effectively resisted the energy level loss and surface defect, a planar N-I-P PSCs with a PCE of 22.38% was achieved, of which open-circuit voltage (V-OC) is 1.16 V and fill factor (FF) is 80.4%. This work taken both energy level adjustment and surface passivation into consideration which may pave the way to further improve the performance of PSCs.