Perovskite quantum dots (CsPbX 3, X = Cl, Br, I) show high luminescence quantum efficiency and sharp emission spectra. They are used as next-generation light emitting device (LED) material to replace organic EL materials and cadmium type quantum dots. A feature of perovskite quantum dots is that it is easy to control their crystal size the emission wavelength by halogen anions. Quantum dot LEDs made from CsPbBr3 and emitting green luminescent light are intensively studied, but CsPbI3 emitting red light was considered difficult to prepare because their crystal structure is unstable. The group around  Takayuki CHIBA has solved this problem by a halogen anion exchange method and have obtained CsPbI3 material of high color purity and very high external quantum efficiency of 21.3 %. The project is done in cooperation with Dainippon Printing and other companies.

JST news release, October 2, 2018