Stable α-CsPbI₃ with extremely red emission for expanding the color gamut

The wider color gamut represents the better reproducibility of the real natural colors. Perovskite materials exhibit promising potential in full-color wide-gamut displays because of the wide tunability and high saturability of their photon emission. However, the full-color wide gamut (>100% Rec.2020) has not been constructed due to the lack of the extreme red primary color (∼700 nm). Herein, the widest color gamut is realized, wherein α-CsPbI₃ is used to generate the extreme red primary color. An in-situ encapsulation approach is advised to stabilize α-CsPbI₃ at room temperature by means of polyvinylpyrrolidone (PVP). The α-CsPbI₃ encapsulated by PVP (denoted as P-CPI) shows highly saturated (FWHM (full width at half maximum) ∼28 nm) and extremely (∼697 nm) red emission. The green emission is provided by P-CPBr (CsPbBr₃ with PVP) which is also synthesized using the universal in-situ encapsulation approach. With the assistance of a commercial GaN chip, the RGB gamut is extended to the widest (151% NTSC, 113% Rec.2020).