CsPbBr3 single crystal film with high optical gain and large area
Lead halide perovskite materials have excellent photoelectric properties such as high light absorption coefficient, carrier mobility, charge diffusion length, and low defect state concentration, and can be used in lasers, light-emitting diodes, and photodetectors. Among them, the perovskite film prepared by the solution spin coating method is widely used in various optoelectronic devices. However, thin-film perovskites have a high density of grain boundaries, leading to a higher density of defect states, causing more radiation-free recombination and affecting carrier lifetime, resulting in poor device performance. Compared with polycrystalline perovskite, single crystal perovskite has a lower defect concentration and a larger carrier mobility, which can further improve device performance. At present, there are still challenges in the preparation of large-area single-crystal perovskite films with high optical gain. Recently, Liu Xinfeng, a researcher at the National Center for Nanosciences of the Chinese Academy of Sciences, collaborated with Peking University professors Xiaoyong Hu and Zhang Qing's research group to prepare a large-area CsPbBr3 single crystal film on a c-plane sapphire substrate. Related research results were published on ACS Nano. This study achieved the growth of large-area CsPbBr3 single crystal films by regulating the growth temperature and substrate concentration of the vapor phase epitaxy. The morphology and structure characterization (Figure 1) show that the film has high crystalline quality and low defect density. The optical gain performance of the single crystal film was studied and analyzed, and its spontaneous amplification radiation threshold was 8 μJ cm-2; the maximum optical gain coefficient could reach 1255±160 cm-1. Further using focused ion beam (FIB) etching technology to process the CsPbBr3 single crystal film into a micro-disk array, the lasing phenomenon of the array is realized (Figure 2), and its lasing threshold is only 1.6 μJ cm-2 . These outstanding properties indicate that the CsPbBr3 single crystal film has a broad application prospect in optical integration in the future. National Nano Center jointly trained Zhong Yangguang as the first author of the paper, and Liu Xinfeng, Hu Xiaoyong and Zhang Qing were the co-corresponding authors of the paper. The research work is supported by the Chinese Academy of Sciences' Strategic Leading Science and Technology Project (Class B), the Key R&D Program of the Ministry of Science and Technology, the National Natural Science Foundation of China, and the Open Project of the Key Laboratory of Low-Dimensional Quantum Physics. The corridor area is a large flow of people in the wet market and the ground is vulnerable to wear and tear, so it is particularly important to choose a suitable pvc floor mat. This hollow design of the hollow Non Slip Mats is very suitable for the corridor area of the wet market. The following is a brief introduction to the hollow Anti Slip Pvc Floor Mat. The first is its anti-slip design: the hollow anti-slip mat uses a special surface texture and material, which has excellent anti-slip performance. This design effectively prevents pedestrians from slipping in the corridor area and improves the safety of walking. Moreover, it is breathable: the hollow design of the floor mat allows air to circulate freely, helps to keep the ground dry, and reduces the growth of mold and bacteria, which is conducive to maintaining the cleanliness of the corridor area. Finally, its wear resistance, hollow non-slip mat made of wear-resistant materials, can withstand high intensity flow of people and friction, extend the service life, reduce ground wear. Anti Slip Flooring Roll,PVC Mat Rolls,Anti Slip Mats Roll,Plastic Mat Roll Jiangyin Yining E-Commerce Co., Ltd , https://www.jypvcmatyining.com
Figure 1. Growth mechanism, morphology and structure characterization diagram of CsPbBr3 single crystal film 
Figure 2. The lasing properties of FIB CsPbBr3 micron disk array