Air-stable all-inorganic perovskite quantum dot inks for multicolor patterns and white LEDs

Recently, all-inorganic perovskite quantum dots (QDs) (CsPbX₃, X = Cl, Br, I) as the emerging semiconductor materials have been intensively studied owing to superior optical properties. Currently, the strategy for preparation of inorganic perovskite QDs mainly focuses on the hot-injection method, but requires inert gas protection and is difficult to mass-produce. In this work, we developed a simple and low-cost strategy for preparing highly luminescent and air-stable all-inorganic perovskite QDs by directly heating perovskite precursors in octane in air. The emission wavelength of CsPbX₃ perovskite QDs can be tunable from ultraviolet (UV) to infrared region by simply controlling their halide composition and display high PLQYs. Moreover, CsPbX₃ perovskite QDs in octane can exist more than half a year in air and the film of CsPbX₃ perovskite QDs also shows good thermal stability and air stability, especially high iodide-substituted CsPbBr_3−xI_x perovskite QDs. The CsPbX₃ perovskite QDs can be easily blended with PDMS and used as color conversion layer on the blue LEDs chip for high-quality white LEDs. Our work opens a window for the potential application of such highly luminescent material in the fields of multicolor LEDs, backlight display and other related optoelectronic devices.