Since 2009, the research on methyl ammonium lead-iodide perovskite solar cells has attracted attention and has become a hot spot in international scientific research and industrial fields. In less than eight years, its photoelectric conversion efficiency has soared from 3% in 2009 to 22.1% in 2017. The methyl ammonium lead iodonium perovskite material has the characteristics of direct band gap, adjustable absorption band gap, strong absorption, and long carrier transport distance, and is the most ideal active absorbing material for photovoltaic devices. The high-quality perovskite film is the key to achieve high photoelectric conversion efficiency of perovskite solar cells. The team of Prof. Wu Chaoxin of the School of Telecommunications has focused on the study of the perovskite layer of an anti-plane heterojunction perovskite solar cell. Recently, the research group has found a simple method to realize a high-quality perovskite film and obtained an inverted plane heterojunction perovskite solar cell with photoelectric conversion efficiency as high as 19.44%. In addition, the method was applied to a flexible battery, and a highly efficient inverting planar heterojunction perovskite flexible cell with a photoelectric conversion efficiency of 17.04% was realized, which is ranked among the highest efficiency of the world's highest flexible thin film solar cell. After the perovskite film was prepared by spin-coating, post-treatment with ammonium thiocyanate (NH4SCN), the perovskite film was decomposed and then recrystallized, resulting in larger crystal grains, better crystallinity, and fewer defects. Perovskite film. This research work was published in November 2017 in an important international journal Advanced Functional Materials (Influence factor 12.12). Title "Halogen-induced Recrystallization of CH3NH3PbI3 Thin Films and Their Application in High-Efficiency Inverse Planar Heterojunction Perovskite Solar Cells" (Hua Dong, Zhaoxin Wu*, et al., Advanced Functional Materials, DOI: 10.1002/ Adfm. 201704836). The first author is Dr. Dong Hua, the young teacher of the research group (the Jiaotong University is the first author and the author of the communication). The article is recommended as the current back cover article (The link of the thesis is https://doi.org/10.1002/adfm.201704836). . In recent years, Professor Wu Chaoxin's team has conducted in-depth research on flexible solar cells and flexible transparent conductive films, and has achieved a series of important results. For example, it has pioneered the development of a low-temperature preparation process for "evaporation-spin coating" perovskite films in the international arena. In 2016, a perovskite solar cell with high-stability a-FAPbI3 was realized, and its photoelectric conversion efficiency was 13.03%. More than one month of stability (Jun Xi, Zhaoxin Wu*, et al, Nano Energy, DOI: 10.1016/j.nanoen. 2016.06.007). Based on this low-temperature film preparation process, the difficulties in the film formation process of the tin-based perovskite are overcome, and an efficient and flexible lead-free perovskite solar cell is realized (Jun Xi, Zhaoxin Wu*, et al., Advanced Materials, 2017. 1606964). . The early stage in the silver nanowire transparent flexible conductive film has important results, to achieve a square resistance less than 10 ohms, and the permeability of more than 88% ultra-thin flexible film (Hua Dong, Zhaoxin Wu*, et al., ACS Appl. Mater. Interfaces2016, 8, 31212−31221; Yaqiu Jiang, Jun Xi, Zhaoxin Wu* et al., Langmuir 2015, 31: 4950-4957). These important results have laid an important foundation for the further realization of ultra-light and high-efficiency thin-film perovskite solar cells. Also involved in this work were Prof. Alex K.-Y. Jen of the University of Washington, USA, Prof. Zhang Lijun of Jilin University, and a project (973) (No. 2013CB328705) from the National Major Scientific Research Project of the Ministry of Science and Technology and a project commissioned by the National Natural Science Foundation of China (No. 11574248) support. Hubei Chengze Diamod Products Co., Ltd. , https://www.ryomaltools.com