Ming-Hui Shang: Institute of Material , Ningbo University of Technology , Ningbo 315016 , People's Republic of China. ORCID
Jing Zhang: Faculty of Science , Ningbo University , Ningbo 315211 , People's Republic of China. ORCID
Peng Zhang: Beijing Computational Science Research Center , 10 West Dongbeiwang Road , Haidian District, Beijing 100193 , China.
Zuobao Yang: Institute of Material , Ningbo University of Technology , Ningbo 315016 , People's Republic of China.
Jinju Zheng: Institute of Material , Ningbo University of Technology , Ningbo 315016 , People's Republic of China.
Md Azimul Haque: Division of Physical Sciences and Engineering , King Abdullah University of Science and Technology , Thuwal 23955-6900 , Kingdom of Saudi Arabia.
Weiyou Yang: Institute of Material , Ningbo University of Technology , Ningbo 315016 , People's Republic of China. ORCID
Su-Huai Wei: Beijing Computational Science Research Center , 10 West Dongbeiwang Road , Haidian District, Beijing 100193 , China.
Tom Wu: School of Materials Science and Engineering , University of New South Wales , Sydney , New South Wales 2052 , Australia. ORCID
The intrinsic poor stability of MAPbI 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 (MABa PbI) 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 MABa PbI is tailored in a wide window of 1.56-4.08 eV. Finally, MABa PbI is used as a capping layer on MAPbI 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.
