Professor Yang Weiqing of Southwest Jiaotong University made important progress in the research of water stability of perovskite materials

Perovskite has excellent photoelectric properties and has a wide application prospect in the fields of light-emitting diode, solar cell, laser, photoelectric detection and so on However, the environmental stability of this kind of materials is poor, which is easily affected by external water, light, oxygen and other factors, resulting in structural degradation and rapid failure, thus limiting the further development of perovskite materials and devices The conventional strategy to improve the environmental stability of perovskite quantum dots, especially the water stability, is to coat a protective layer on the surface of the material, such as hydrophobic ligands, organic polymers, silica, alumina, etc., to isolate the material from the external environment However, the existence of the protective layer often affects the charge transfer of the perovskite quantum dots, which affects the performance of the photoelectric conversion devices Therefore, it is urgent to develop a "coating free" strategy to improve the intrinsic stability Recently, Professor Yang Weiqing from the school of materials, Southwest Jiaotong University has made important progress in the research of water stability of perovskite materials, and published cover articles online on small, an international famous journal, with Southwest Jiaotong University as the first author This achievement has been greatly supported by NSFC, Sichuan Provincial Science and technology department international cooperation project, Central University Basic Research Fund and other projects, Southwest Jiaotong University and School of materials Under the guidance of Professor Yang Weiqing, young teacher Li Wen and researcher Yan Wei of Institute of optoelectronic technology of Chinese Academy of Sciences, Xie Meilin, a master student of Southwest Jiaotong University, put forward a new method of perovskite aqueous phase stripping, and prepared a quasi-2D cspbbr 3 nano sheet with high intrinsic water stability It effectively overcomes the problem of decomposition in water caused by the intrinsic ion characteristics of perovskite materials This kind of quasi two dimensional csppbbr 3 nano sheet prepared by "aqueous phase stripping" method has high intrinsic water stability, and can still maintain 87% of the luminous intensity after being dispersed in water for 168 hours Compared with the traditional perovskite quantum dots, its optical stability has also been significantly improved This work provides a new idea for the study of improving the stability of perovskite materials Relevant research results were published in small (DOI: 10.1002/small.201901994) under the title of "aqueous phase unfolding quasi-2D cspbbr 3 nanosheets with ultra high intrinsic water stability".