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ScienceDirectMaterials Today: Proceedings 00 (2018) 0000–0000 www.materialstoday.com/proceedings

AFM2 2017

Cation-dependent ionic transport in hybrid perovskite materialsYicheng Zhao1*, Wenke Zhou1, Qing Zhao1

State Key Laboratory for Mesoscopic Physics and Electron Microscopy Laboratory, School of Physics, Peking University, Beijing 100871, China

Abstract

Organic-inorganic hybrid perovskite solar cells (PSCs) exhibits a 22.1% record certified efficiency recently, while the long-term stability issue still remains as an Achilles heel for their commercialization. Although the material itself passes damp heat stability test, a fast degradation behavior is still observed at the early stage, the so-called ‘burn-in’ degradation, implying an ion migration-related destruction in perovskite-based devices. Here we systematically investigated the role of organic cation (e.g. CH3NH3

+) plays in the ionic transport property of perovskite materials via a series of cryogenic experiments with different light illumination. We found a reduced energy barrier of ion migration by light excitation in organic-cation-based perovskites; however, the property of light-enhanced ion migration is inhibited by inorganic cation incorporation into perovskites. The quantitative analysis enables us to extract the exact value of energy barrier under different condition by using Arrhenius equation, showing a 5-fold decrease in the energy barrier in organic-cation-based perovskite ( i.e. CH3NH3PbI3) when the light-intensity increases from 0 to 20 mW cm-2. We close by demonstrating a ultra-stable perovskite solar cell with the active layer of CsPbI 2Br, retaining 99% percents of the initial value after 1500 hours’ continuous output. Our work points out an important direction to improve the intrinsic stability of perovskite solar cells, or other photo-electronic devices.

* Corresponding author. Tel.: 86-15600604887.E-mail address: zhaoyicheng@pku.edu.cn

© 2018 Elsevier Ltd. All rights reserved.Selection and/or Peer-review under responsibility of 2017 International Workshop on Atomic Force Microscopy for Advanced Functional Materials.

Keywords: Perovskite; ion migration; light.

2214-7853 © 2018 Elsevier Ltd. All rights reserved.Selection and/or Peer-review under responsibility of 2017 International Workshop on Atomic Force Microscopy for Advanced Functional Materials.