Facile In Situ Fabrication of Cs4PbBr6/CsPbBr3 Nanocomposite Containing Polymer Films for Ultrawide Color Gamut Displays

A modified supersaturated recrystallization method for in situ fabrication of Cs4PbBr6/CsPbBr3 nanocomposite containing polymer films is reported. This facile and efficient strategy can be easily carried out at room temperature, and minimizes the contact time between CsPbBr3 nanocrystals and water and oxygen molecules during the formation of perovskite film, passivating the perovskite nanocrystals. Through the approach, the dual protection of Cs4PbBr6 and polymer matrix enhances the water stability and photostability of emitting CsPbBr3. Even after being immersed in water for 30 days, the Cs4PbBr6/CsPbBr3@PMMA film still retains a bright green fluorescence. Moreover, combining the as-prepared green-emitting Cs4PbBr6/CsPbBr3@PMMA and a red-emitting CdSe/ZnS based quantum dots (QDs) polymer film with blue light emitting diode (LED) chips as the backlight, a high performance liquid crystal display (LCD) is demonstrated. The color gamut of the demonstrated display is 131% and 98% that of the NTSC 1953 and Rec.2020, respectively. The combination of better stability and improved color purity of the perovskite material intuitively provides a viable approach for LCD backlights.