Highly efficient CsPbBr@glass@polyurethane composite film as flexible liquid crystal display backlight.

Inorganic lead halide perovskite quantum dots (CsPbX QDs (X = Cl, Br, or I)) have attracted more and more attention due to their high absorption coefficient, narrow emission band, high quantum efficiency, and tunable emission wavelength. However, CsPbX QDs are decomposed when exposed to bright light, heat, moisture, ., which leads to severe luminous attenuation and limits their commercial application. In this paper, CsPbBr@glass materials were successfully synthesized by a one-step self-crystallization method, including melting, quenching and heat treatment processes. The stability of CsPbBr QDs was improved by embedding CsPbBr QDs into zinc-borosilicate glass. Then, the CsPbBr@glass was combined with polyurethane (PU) to form a flexible composite luminescent film CsPbBr@glass@PU. This strategy enables the transformation of rigid perovskite quantum dot glass into flexible luminescent film materials and further improves the photoluminescence quantum yield (PLQY) from 50.5% to 70.2%. The flexible film has good tensile properties, and its length can be strained 5 times as long as the original length. Finally, a white LED was encapsulated by combining CsPbBr@glass@PU film and red phosphor KSiF:Mn with a blue LED chip. The good performance of the obtained CsPbBr@glass@PU film indicates that it has potential application in flexible liquid crystal displays (LCDs) as a backlight source.