The intrinsic poor stability of MAPbI3 hybrid perovskites in the ambient environment remains as the major challenge for photovoltaic applications. In this work, complementary first-principles calculations and experimental characterizations reveal that metal cation alloyed perovskite (MABaxPb1–xI3) can be synthesized and exhibit substantially enhanced stability via forming stronger Ba–I bonds. The Ba–Pb alloyed perovskites remain phase-pure in ambient air for more than 15 days. Furthermore, the bandgap of MABaxPb1–xI3 is tailored in a wide window of 1.56–4.08 eV. Finally, MABaxPb1–xI3 is used as a capping layer on MAPbI3 in solar cells, resulting in significantly improved power conversion efficiency (18.9%) and long-term stability (>30 days). Overall, our results provide a simple but reliable strategy toward stable less-Pb perovskites with tailored physical properties.
Bibliographical noteKAUST Repository Item: Exported on 2020-10-01
Acknowledgements: This work was supported by the National Natural Science Foundation of China (NSFC, Grant Nos. 11547033 and 51302137), the Scientific Research Foundation for Returned Overseas Chinese Scholars, Zhejiang Provincial Natural Science Foundation of China (LY18F040008), the Natural Science Foundation of Ningbo Municipal Government (Grant No. 2015A610032 and 2016A610108), and the Foundation of Education bureau of Zhejiang Province (Y201533502). Work at Beijing CSRC is supported by the National Key Research and Development Program of China Grant No. 2016YFB0700700 and NSAF joint program under Grant Number U1530401.