title: Controllable self-induced passivation of hybrid lead iodide perovskites toward high performance solar cells.
abstract: To improve the performance of the polycrystalline thin film devices, it requires a delicate control of its grain structures. As one of the most promising candidates among current thin film photovoltaic techniques, the organic/inorganic hybrid perovskites generally inherit polycrystalline nature and exhibit compositional/structural dependence in regard to their optoelectronic properties. Here, we demonstrate a controllable passivation technique for perovskite films, which enables their compositional change, and allows substantial enhancement in corresponding device performance. By releasing the organic species during annealing, PbI2 phase is presented in perovskite grain boundaries and at the relevant interfaces. The consequent passivation effects and underlying mechanisms are investigated with complementary characterizations, including scanning electron microscopy (SEM), X-ray diffraction (XRD), time-resolved photoluminescence decay (TRPL), scanning Kelvin probe microscopy (SKPM), and ultraviolet photoemission spectroscopy (UPS). This controllable self-induced passivation technique represents an important step to understand the polycrystalline nature of hybrid perovskite thin films and contributes to the development of perovskite solar cells judiciously.
authors: Department of Materials Science and Engineering and ‡California NanoSystems Institute, University of California , Los Angeles, California 90095, United States.
authors: Qi
authors: Q
authors: Chen
authors: Huanping
authors: H
authors: Zhou
authors: Tze-Bin
authors: TB
authors: Song
authors: Song
authors: S
authors: Luo
authors: Ziruo
authors: Z
authors: Hong
authors: Hsin-Sheng
authors: HS
authors: Duan
authors: Letian
authors: L
authors: Dou
authors: Yongsheng
authors: Y
authors: Liu
authors: Yang
authors: Y
authors: Yang