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

Abstract 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.