Highly Efficient Integrated Perovskite/Organic Bulk-Heterojunction Solar Cells Combining Layer-By-Layer Processing Ternary Systems and Interface Modification

Integrated perovskite/organic bulk-heterojunction (BHJ) solar cells (IPOSCs) have been developed to extend the photoresponse of perovskites in the near-infrared region. Serious charge recombination at the perovskite/organic BHJ interface always reduces the open-circuit voltage (V_OC) and filling factor (FF). Here, we first prepare IPOSCs with layer-by-layer processing ternary BHJ (PTLBL), in which the acceptor mixture consists of Y6 and PC₆₁BM. PC₆₁BM addition inhibited the charge recombination in IPOSCs and induced PTLBL devices with a champion power conversion efficiency (PCE) of 20.85%. Then, we modified the perovskite surface with vanadium acetylacetonate (VAcac) and zirconium acetylacetonate (ZrAcac), which reduced the perovskite surface potential, enhanced the charge transfer between the perovskite and BHJ, and regulated the carrier extraction. The PTLBL devices with VAcac and ZrAcac exhibit champion PCEs of 21.06% and 21.32%, respectively, because of the further improvement in V_OC and FF. Combining layer-by-layer processing of ternary BHJ with interfacial materials provides a feasible strategy for simultaneously improving all the parameters of IPOSCs.