title: Room-temperature and solution-processed copper iodide as the hole transport layer for inverted planar perovskite solar cells.
abstract: Inverted planar heterojunction perovskite solar cells with poly (3,4-ethylenedioxythiophene):poly (styrenesulfonate) sulfonic acid (
  PSS) as the hole transport layer (HTL) have attracted significant attention during recent years. However, these devices suffer from a serious stability issue due to the acidic and hygroscopic characteristics of
  PSS. In this work, we demonstrate a room-temperature and solution-processed CuI film which is used as the HTL for inverted perovskite solar cells. As a result, an impressive PCE of 16.8% is achieved by the device based on the CuI HTL. Moreover, the unsealed CuI-based device displays enhanced air stability compared to the
  PSS-based device. In addition, the fabrication of the CuI HTL is a simple and time-saving procedure without any post-treatment, thus making it a promising candidate as the HTL in inverted perovskite solar cells and a potential target for efficient flexible and tandem 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.
authors.forename: Weihai
authors.initials: W
authors.lastname: Sun
authors.forename: Senyun
authors.initials: S
authors.lastname: Ye
authors.forename: Haixiao
authors.initials: H
authors.lastname: Rao
authors.forename: Yunlong
authors.initials: Y
authors.lastname: Li
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Liu
authors.forename: Lixin
authors.initials: L
authors.lastname: Xiao
authors.forename: Zhijian
authors.initials: Z
authors.lastname: Chen
authors.forename: Zuqiang
authors.initials: Z
authors.lastname: Bian
authors.forename: Chunhui
authors.initials: C
authors.lastname: Huang