title: Insights into the Influence of Work Functions of Cathodes on Efficiencies of Perovskite Solar Cells.
abstract: Though various efforts on modification of electrodes are still undertaken to improve the efficiency of perovskite solar cells, attributing to the large scope of these methods, it is of significance to unveil the working principle systematically. Herein, inverted perovskite solar cells based on indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS)/CH3NH3PbI3/phenyl-C61-butyric acid methyl ester (PC61BM)/buffer metal/Al are constructed. Through the choice of different buffer metals to tune work function of the cathode, the contact nature of the active layer with the cathode could be manipulated well. In comparison with the device using Au/Al as the electrode that shows an unfavorable band bending for conducting the excited electrons to the cathode, the one with Ca/Al presents a dramatically improved efficiency over 17.1%, ascribed to the favorable band bending at the interface of the cathode with the active layer. Details for tuning the band bending and the corresponding charge transfer mechanism are given in a systematic manner. Thus, a general guideline for constructing perovskite photovoltaic devices efficiently is provided.
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Shizhong
authors.initials: S
authors.lastname: Yue
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Shudi
authors.initials: S
authors.lastname: Lu
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Kuankuan
authors.initials: K
authors.lastname: Ren
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Kong
authors.initials: K
authors.lastname: Liu
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Azam
authors.affiliation: Institut für Physik and IMN MacroNano@ (ZIK), Technische Universität Ilmenau, 98693, Ilmenau, Germany.
authors.forename: Dawei
authors.initials: D
authors.lastname: Cao
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Zhijie
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Institut für Physik and IMN MacroNano@ (ZIK), Technische Universität Ilmenau, 98693, Ilmenau, Germany.
authors.forename: Yong
authors.initials: Y
authors.lastname: Lei
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Shengchun
authors.initials: S
authors.lastname: Qu
authors.affiliation: Key Laboratory of Semiconductor Materials Science, Beijing Key Laboratory of Low Dimensional Semiconductor Materials and Devices, Institute of Semiconductors, Chinese Academy of Sciences, Beijing, 100083, P. R. China.|College of Materials Science and Opto-Electronic Technology, University of Chinese Academy of Sciences, Beijing, 100049, China.
authors.forename: Zhanguo
authors.initials: Z
authors.lastname: Wang
keywords: band bending; buffer metal; perovskite solar cells; work function