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Dual Interfacial Design for Efficient CsPbI 2 Br Perovskite Solar Cells with Improved Photostability
Author(s) -
Tian Jingjing,
Xue Qifan,
Tang Xiaofeng,
Chen Yuxuan,
Li Ning,
Hu Zhicheng,
Shi Tingting,
Wang Xin,
Huang Fei,
Brabec Christoph J.,
Yip HinLap,
Cao Yong
Publication year - 2019
Publication title -
advanced materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.707
H-Index - 527
eISSN - 1521-4095
pISSN - 0935-9648
DOI - 10.1002/adma.201901152
Subject(s) - materials science , perovskite (structure) , anode , passivation , wetting , cathode , halide , crystallinity , dopant , energy conversion efficiency , homo/lumo , chemical engineering , optoelectronics , nanotechnology , layer (electronics) , inorganic chemistry , doping , chemistry , electrode , composite material , organic chemistry , molecule , engineering
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 polymer poly[5,5′‐bis(2‐butyloctyl)‐(2,2′‐bithiophene)‐4,4′‐dicarboxylate‐ alt ‐5,5′‐2,2′‐bithiophene] (PDCBT) as anode interlayer. First, the interfacial dipole formed at the cathode interface reduces the workfunction of SnO 2 , while PDCBT with deeper‐lying highest occupied molecular orbital (HOMO) level provides a better energy‐level matching at the anode, leading to a significant enhancement in open‐circuit voltage ( V oc ) of the PVSCs. Second, the PN4N layer can also tune the surface wetting property to promote the growth of high‐quality all‐inorganic perovskite films with larger grain size and higher crystallinity. Most importantly, both theoretical and experimental results reveal that PN4N and PDCBT can interact strongly with the perovskite crystal, which effectively passivates the electronic surface trap states and suppresses the photoinduced halide segregation of CsPbI 2 Br films. Therefore, the optimized CsPbI 2 Br PVSCs exhibit reduced interfacial recombination with efficiency over 16%, which is one of the highest efficiencies reported for all‐inorganic PVSCs. A high photostability with a less than 10% efficiency drop is demonstrated for the CsPbI 2 Br PVSCs with dual interfacial modifications under continuous 1 sun equivalent illumination for 400 h.