Dual Interfacial Design for Efficient CsPbI2Br Perovskite Solar Cells with Improved Photostability

• DOI: 10.1002/adma.201901152
• Publication Date: 2019-04-12T00:59:04Z
• Authors: Jingjing Tian; Qifan Xue; Xiaofeng Tang; Yuxuan Chen; Ning Li; Zhicheng Hu; Tingting Shi; Xin Wang; Fei Huang; Christoph J. Brabec; Hin‐Lap Yip; Yong Cao
• Keywords: Passivation; HOMO/LUMO

Abstract A synergic interface design is demonstrated for photostable inorganic mixed‐halide perovskite solar cells (PVSCs) by applying an amino‐functionalized polymer (PN4N) as cathode interlayer and a dopant‐free hole‐transporting poly[5,5′‐bis(2‐butyloctyl)‐(2,2′‐bithiophene)‐4,4′‐dicarboxylate‐ alt ‐5,5′‐2,2′‐bithiophene] (PDCBT) anode interlayer. First, the interfacial dipole formed at reduces workfunction of SnO 2 , while PDCBT with deeper‐lying highest occupied molecular orbital (HOMO) level provides better energy‐level matching anode, leading to significant enhancement in open‐circuit voltage ( V oc ) PVSCs. Second, PN4N layer can also tune surface wetting property promote growth high‐quality all‐inorganic films larger grain size higher crystallinity. Most importantly, both theoretical experimental results reveal that interact strongly crystal, which effectively passivates electronic trap states suppresses photoinduced halide segregation CsPbI Br films. Therefore, optimized PVSCs exhibit reduced recombination efficiency over 16%, one efficiencies reported high photostability less than 10% drop dual modifications under continuous 1 sun equivalent illumination 400 h.