Recently, Han Keli, a researcher of the Complex Molecular System Reaction Dynamics Group of Dalian Institute of Chemical Physics, Chinese Academy of Sciences, made progress in the research of non-lead double perovskite nanocrystals. The team first synthesized a non-lead double perovskite with cubic phase. Cs2AgBiX6 (X = Cl, Br, I) nanocrystals, and found that its hot carriers have ultra-fast cooling time (less than 1ps, 1ps = 10-12s), indicating that the material is a good luminescent material.
The lead-containing perovskite nanocrystalline CsPbX3 (X=Cl, Br, I) has the advantages of large absorption coefficient, high luminescence quantum yield, and easy band gap adjustment, and is widely used in light emitting diodes (LEDs), nano lasers, solar cells, and In the related research of photoelectric detectors, but the lead contained in the heavy metal elements will cause harm to the environment and humans, limiting its commercial application. The search for non-toxic and good performance of non-lead perovskite has become a hot topic in this field. And difficult points.
Researchers attempted to replace lead with less toxic Bi elements to form low-dimensional perovskite structures. The team successfully synthesized Bi-containing non-lead perovskite nanocrystalline Cs3Bi2Br9 for the first time in 2017 and revealed that Its luminescence kinetics mechanism. Based on this, the team members further synthesized the Cs2AgBiBr6 double perovskite nanocrystals using the solution method. The introduced Ag+ ions can form three-dimensional cubic phase perovskites with Bi3+ ions through the use of different halogen elements ( Cl, Br, I) enables the nanocrystals to adjust their luminescence spectra in the 395-575nm range. Hot carrier kinetics studies have found that the material has ultrafast hot carrier cooling time (less than 1ps). Similar to the hot-carrier kinetics of the lead-containing perovskite nanocrystals, the non-lead perovskite nanocrystals are likely to replace the current lead-containing perovskite nanocrystals and have very broad application prospects. The study also proposes a new scheme to improve the material properties by reducing surface defects.
Relevant research results were published as a hot article in "German Applied Chemistry". This research was funded by the National Natural Science Foundation of China.
