Independent dispersed and highly water-oxygen environment stable FAPbBr3 QDs-polymer composite for down-conversion display films

• The in-situ polymerization via illuminating and methyl methacrylate was firstly proposed. • The hybrid FAPbBr 3 QDs-polymer nanocomposites show enhanced stability and fluorescence. • The transparent nanocomposite films with strong blue, green and red emission were prepared in large area. • High color temperature and lumen efficiency WLED was constructed. It has been proved that perovskite quantum dots (QDs) have great potential in optoelectronic devices because of their excellent optical performance. However, low stability against water and oxygen environment hinders the commercial application of down-conversion display films on account of its highly ionic nature and low formation energy. Here, we demonstrate a convenient method to obtain a uniform, large-area water-oxygen-resistant quantum dot-polymer composite film via illuminating FAPbBr 3 QDs and methyl methacrylate (MMA) under white light emitting diode. We find that FAPbBr 3 QDs act as photo initiators, leading to the polymerization of organic monomers around the quantum dots. The obtained FAPbBr 3 QDs-polymer nanocomposites are independently dispersed coated with about 10 nm thick polymerized methyl methacrylate (PMMA). Due to the well protection of covered PMMA, the FAPbBr 3 QDs/PMMA nanocomposites show high tolerance to water and oxygen, and the increased PLQY and lifetime indicate the reduction of non-radiative recombination centers. Furthermore, the FAPbBr 3 QDs/PMMA nanocomposites are easy to produce large area films, and no agglomeration during films production by knife coating process. Then uniform, strong fluorescence, transparent and stable blue, green and red nanocomposite films can be prepared by optimizing the viscosity via controlling the reaction time. Finally, white LED was fabricated with a Lumen Efficiency of 80.4 m/W and Color Rendering Index of 90. Our work suggests that illuminated polymerization of perovskite quantum dots under white light emitting diode provides a simple and effective method to commercialization