Fig. (A) Electrochemical impedance spectra of PSCs with different PbI2 contents at 0.8V bias; (B) Composite impedances of PSCs with different PbI2 contents under different biases; (C) Fluorescence lifetime spectra of CH3NH3PbI3 films with different PbI2 contents. Researcher Fang Xiaodong of the Institute of Laser Technology, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, has made new progress in the research of perovskite solar cells. The relevant research work is based on Credible evidence for the passivation effect of remnant PbI2 in CH3NH3PbI3 films in improving The performance of perovskite solar cells was published in the Nanoscale magazine (Nanoscale, 2016, 8: 6600-6608). Perovskite solar cells (PSCs) with perovskite-type organometallic halides as light-absorbing materials are the latest developments in thin-film solar cells. The highest certified photoelectric conversion efficiency has reached 22.1%, exceeding the maximum of polycrystalline silicon solar cells. The photoelectric conversion efficiency is 21.3%, so it has a great application prospect. CH3NH3PbI3 is the most typical and commonly used light-absorbing material in PSCs. PbI2 remains in the preparation process of CH3NH3PbI3 films. The role of residual PbI2 is still controversial. One view is that it can play a role in passivation to improve battery performance. One side of the point of view is exactly the opposite. The researchers in this group believe that the key to whether PbI2 can play a passivation and improve battery performance lies in the location and amount of PbI2 present. Dr. Wang Shimao of the research group obtained CH3NH3PbI3 films with different PbI2 contents and positions by controlling various parameters during the preparation of CH3NH3PbI3 films. By measuring the fluorescence lifetime of CH3NH3PbI3 films and measuring the composite current of dark current and charge in the corresponding PSCs, they found that the fluorescence lifetime of CH3NH3PbI3 films increases gradually as the content of PbI2 at the interface of CH3NH3PbI3/TiO2 electron transport layer increases. The resistance also gradually increases, that is, the recombination of the charge in the battery is gradually suppressed, which indicates that PbI2 at this interface can play a passivation effect, inhibiting the recombination of electrons in the TiO2 electron transport layer and holes in the CH3NH3PbI3 film; when the residual PbI2 is mainly When located between CH3NH3PbI3 particles, the fluorescence lifetime of the CH3NH3PbI3 film and the composite impedance of the battery significantly increase, which is the inhibition effect of the passivation of CH3NH3PbI3 particles on the charge recombination. This study provides direct evidence for the passivation of PbI2 in PSCs and has a certain reference value for future development of PSCs. The above research work has been supported by the National Natural Science Foundation of China, the China Postdoctoral Science Foundation, the "973" Program and the Key Laboratory of Novel Thin Film Solar Cells of the Chinese Academy of Sciences. cylinder,High Quality cylinder,cylinder Details, CN Nanjing Toutru Trading Co., Ltd. , https://www.tcdoorlock.com