Interface Engineering for All-Inorganic CsPbI2 Br Perovskite Solar Cells with Efficiency over 14

Lei Yan; Qifan Xue; Meiyue Liu; Zonglong Zhu; Jingjing Tian; Zhenchao Li; Zhen Chen; Ziming Chen; He Yan; Hin-Lap Yip; Yong Cao

doi:10.1002/adma.201802509

Interface Engineering for All-Inorganic CsPbI₂ Br Perovskite Solar Cells with Efficiency over 14

Adv Mater. 2018 Jul 3:e1802509. doi: 10.1002/adma.201802509. Online ahead of print.

Authors

Lei Yan¹, Qifan Xue¹, Meiyue Liu¹, Zonglong Zhu², Jingjing Tian¹, Zhenchao Li¹, Zhen Chen¹, Ziming Chen¹, He Yan², Hin-Lap Yip^{1

3}, Yong Cao¹

Affiliations

¹ Institute of Polymer Optoelectronic Materials and Devices, State Key Laboratory of Luminescent Materials and Devices, South China University of Technology, Guangzhou, 510640, P. R. China.
² Department of Chemistry, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, 999077, Hong Kong.
³ Innovation Center for Printed Photovoltaics, South China Institute of Collaborative Innovation, Dongguan, 523808, P. R. China.

PMID: 29971864
DOI: 10.1002/adma.201802509

Abstract

In this work, a SnO₂ /ZnO bilayered electron transporting layer (ETL) aimed to achieve low energy loss and large open-circuit voltage (V_oc ) for high-efficiency all-inorganic CsPbI₂ Br perovskite solar cells (PVSCs) is introduced. The high-quality CsPbI₂ Br film with regular crystal grains and full coverage can be realized on the SnO₂ /ZnO surface. The higher-lying conduction band minimum of ZnO facilitates desirable cascade energy level alignment between the perovskite and SnO₂ /ZnO bilayered ETL with superior electron extraction capability, resulting in a suppressed interfacial trap-assisted recombination with lower charge recombination rate and greater charge extraction efficiency. The as-optimized all-inorganic PVSC delivers a high V_oc of 1.23 V and power conversion efficiency (PCE) of 14.6%, which is one of the best efficiencies reported for the Cs-based all-inorganic PVSCs to date. More importantly, decent thermal stability with only 20% PCE loss is demonstrated for the SnO₂ /ZnO-based CsPbI₂ Br PVSCs after being heated at 85 °C for 300 h. These findings provide important interface design insights that will be crucial to further improve the efficiency of all-inorganic PVSCs in the future.

Keywords: all-inorganic perovskite solar cells; bilayered electron transporting layer; high efficiency; interface engineering.