In recent years, the problems of environment and energy become more and more violent. Clean and renewable solar energy has aroused wide attention among scientific community and industry. Perovskite solar cells (PerSCs) have developed rapidly due to their easy fabrication, low cost and high efficiency. Generally, lead halides are the most popular lead sources for perovskite active layers. Recently, lead acetate (Pb(Ac)2) has shown its superiority as a potential candidate to replace the traditional lead halides because of its simple process. To date, the PerSCs based on Pb(Ac)2 precursors have shown relatively low performance in comparison to those based on lead halide precursors.

Recently, Prof. Rui Zhu and Prof. Qihuang Gong at Department of Physics, Peking University working with the collaborators, Dr. Feng Liu from Lawrence Berkeley National Laboratory, Prof. Thomas P. Russell from University of Massachusetts, Dr. Wei Zhang and Prof. Henry J. Snaith from University of Oxford, demonstrated a strategy to improve the device performance for the PerSCs based on Pb(Ac)2 precursors. They have used trace amounts of a methylammonium bromide (MABr) additive in the Pb(Ac)2-based precursor solution. The MABr additive is shown to improve the perovskite film morphology, crystallinity and optoelectronic properties, leading to enhanced device performance. A champion power conversion efficiency of 18.32% with a stabilized output efficiency of 17.60% has been achieved in the inverted planar heterojunction PerSCs. These results hold promise for Pb(Ac)2 as a lead source for PerSCs.

This work was published in Advanced Functional Materials (Adv. Funct. Mater. 2016, 26(20), 3508. DOI: 10.1002/adfm.201601175) as the inside back cover. Rui Zhu and Thomas P. Russell are the corresponding authors of this paper. Lichen Zhao and Deying Luo contributed equally to this work.

This work was supported by the Ministry of Science and Technology of China, the National Natural Science Foundation of China, State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, 2011 Collaborative Innovation Center of Quantum Matter, China, Collaborative Innovation Center of Extreme Optics, 1000 Talents Program for Young Scientists of China, United States Department of Energy and Lawrence Berkeley National Laboratory.