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Heterojunction Engineering for High Efficiency Cesium Formamidinium Double‐Cation Lead Halide Perovskite Solar Cells
Author(s) -
Wu Yihui,
Wang Peng,
Wang Shubo,
Wang Zenghua,
Cai Bing,
Zheng Xiaojia,
Chen Yu,
Yuan Ningyi,
Ding Jianning,
Zhang WenHua
Publication year - 2018
Publication title -
chemsuschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.412
H-Index - 157
eISSN - 1864-564X
pISSN - 1864-5631
DOI - 10.1002/cssc.201702221
Subject(s) - formamidinium , perovskite (structure) , caesium , halide , energy conversion efficiency , heterojunction , materials science , optoelectronics , chemical engineering , nanotechnology , chemistry , inorganic chemistry , organic chemistry , engineering
It is essential to minimize the interfacial trap states and improve the carrier collection for high efficiency perovskite solar cells (PSCs). Herein, we present a facile method to construct a p‐type graded heterojunction (GHJ) in normal PSCs by deploying a gradient distribution of hole‐transporting materials (poly[bis(4‐phenyl)(2,4,6‐trimethylphenyl)amine], PTAA, in this case) in the shallow perovskite layer. The formation of the GHJ structure facilitates charge transfer and collection, and passivates interfacial trap states, thus delivering a power conversion efficiency (PCE) of 20.05 % along with steady output efficiency of 19.3 %, which is among the highest efficiencies for cesium formamidinium (Cs–FA) lead halide PSCs. Moreover, the unencapsulated devices based on these (Cs–FA) lead halide perovskites show excellent long‐term stability; more than 95 % of their initial PCE can be retained after 1440 h storage under ambient conditions. This study may provide an effective strategy to fabricate high‐efficiency PSCs with great stability.