title: High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer.
abstract: During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid (
  PSS) as the hole transport material (HTM), the hydrophilicity of the
  PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm(-2) and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the
  PSS layer, indicating that CuOx could be a promising HTM for replacing
  PSS in inverted planar heterojunction perovskite solar cells.
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn and Institute of Modern Optics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China.
authors.forename: Weihai
authors.initials: W
authors.lastname: Sun
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Senyun
authors.initials: S
authors.lastname: Ye
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Haixia
authors.initials: H
authors.lastname: Rao
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Weibo
authors.initials: W
authors.lastname: Yan
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Haitao
authors.initials: H
authors.lastname: Peng
authors.affiliation: Institute of Modern Optics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Institute of Modern Optics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China.
authors.forename: Shufeng
authors.initials: S
authors.lastname: Wang
authors.affiliation: Institute of Modern Optics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China.
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Institute of Modern Optics and State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, P. R. China.
authors.forename: Lixin
authors.initials: L
authors.lastname: Xiao
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Zuqiang
authors.initials: Z
authors.lastname: Bian
authors.affiliation: Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Rare Earth Materials Chemistry and Applications, Peking University, Beijing, 100871, P. R. China. bianzq@pku.edu.cn zwliu@pku.edu.cn.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Huang