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Translator: News Agency of BIT, Lv Yuetong

Editor: News Center of BIT, Zhao Jie

　　Recently, the magazine, Advanced Materials , have published online a paper of the joint research results about the perovskite solar cells. The research was carried out by research group of Professor Chen Qi from Beijing Institute of Technology (BIT) and research group of Professor Zhou Huanping from Peking University. The paper is named Chemical Reduction of Intrinsic Defects in Thicker Heterojunction Planar Perovskite Solar Cells ，(DOI: 10.1002/adma.201606774), and its first writer is Dr. Liu Zonghao.

　　In recent years, the organic-inorganic hybrid perovskite solar cell has attracted tons of attention with its high efficiency and low cost. What’s more, how to construct thick and low defect perovskite heterojunction is a key research point of commercialization of perovskite solar cells in the future, as it is associated with the conformity rate and cost of perovskite cell directly.

　　Researchers from research groups of Professor Chen Qi and Professor Zhou Huanping added cheap commercialized methylamine ethanol solution into perovskite precursor solution as an additive so as to get the high-quality perovskite film, over 600 nm thick, and related components. According to the experiment, there are a few important features to be noted. Firstly, the use of methylamine alcohol solution can inhibit the creation of iodine, protect the device from the harmful effect of grain boundary, and greatly enhance the precise control of precursor material ratio. Secondly, Methylamine ethanol additive can regulate the colloidal particle size of perovskite precursor solution by coordination, lower the concentration of lodine-lead complex and further influence the growth process and quality of perovskite film. Thirdly, a certain amount of Methylamine ethanol additive also can reduce nucleation rate in crystallization process, improve the growth of perovskite grain and eliminate the grain boundary adverse effect for device performance. Compared with the reference samples, perovskite film made with methylamine ethanol additives has longer fluorescence lifetime of 511.9 ns while it was previously only 271.4 ns, lower energy band edge electron configuration disorder, the Uhl Bach energy of 21.4 eV while it was previously 24.7 eV and longer spin lifetime (31 ps，14K). And its defect density falls to one-tenth of the previous density, 1.5×10¹⁵ cm³ and 1.38×10¹⁶ cm³ respectively. In this simple way, perovskite solar cells based on 600 nm thick high-quality perovskite film acquire 20.02% photoelectric conversion efficiency and more than 19% stable output efficiency. More importantly, this method features simple process and strong universality, which has a great competitive edge in the industrialized application.

　　This work is supported by NSFC (Natural Science Foundation of China) and Thousand Youth Talents Plan Project Foundation

　　The writer of this thesis are Zonghao Liu, Junnan Hu, Haoyang Jiao, Liang Li, Guanhaojie Zheng, Yihua Chen, Yuan Huang, Qing Zhang, Chao Shen, Qi Chen, and Huanping Zhou.

　　Advanced Materials 2017, DOI: 10.1002/adma.201606774.