Properties of Contact and Bulk Impedances in Hybrid Lead Halide Perovskite Solar Cells Including Inductive Loop Elements

详细信息    查看全文

• 作者：Antonio Guerrero ; Germà Garcia-Belmonte ; Ivan Mora-Sero ; Juan Bisquert ; Yong Soo Kang ; T. Jesper Jacobsson ; Juan-Pablo Correa-Baena ; Anders Hagfeldt
• 刊名：Journal of Physical Chemistry C
• 出版年：2016
• 出版时间：April 21, 2016
• 年：2016
• 卷：120
• 期：15
• 页码：8023-8032
• 全文大小：568K
• 年卷期：0
• ISSN：1932-7455

文摘

Impedance spectroscopy offers access to all the different electronic and ionic processes taking place simultaneously in an operating solar cell. To date, its use on perovskite solar cells has been challenging because of the richness of the physical processes occurring within similar time domains. The aim of this work is to understand the general impedance response and propose a general equivalent circuit model that accounts for the different processes and gives access to quantitative analysis. When the electron-selective contacts and the thickness of the perovskite film are systematically modified, it is possible to distinguish between the characteristic impedance signals of the perovskite layer and those arising from the contacts. The study is carried out using mixed organic lead halogen perovskite (FA_0.85MA_0.15Pb(I_0.85Br_0.15)₃) solar cells with three different electron-selective contacts: SnO₂, TiO₂, and Nb₂O₅. The contacts have been deposited by atomic layer deposition (ALD), which provides pinhole-free films and excellent thickness control in the absence of a mesoporous layer to simplify the impedance analysis. It was found that the interfacial impedance has a rich structure that reveals different capacitive processes, serial steps for electron extraction, and a prominent inductive loop related to negative capacitance at intermediate frequencies. Overall, the present report provides insights into the impedance response of perovskite solar cells which enable an understanding of the different electronic and ionic processes taking place during device operation.