Highly Photoluminescent Yb-Doped CsPbBrI₂ Nanocrystals in Ethylene Vinyl Acetate Composite Films for Wide Color Gamut Backlight Displays

Metal halide CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) have been widely studied because of their high photoluminescent quantum yield (PLQY) and tunable emission wavelength. However, their weak hydrothermal stability greatly limits the use of CsPbX3 NCs under harsh conditions. This work successfully solved the problem of poor stability of CsPbX3 NCs through the ethylene vinyl acetate (EVA) film coating strategy and expanded the application range of CsPbX3 NCs. In addition, we demonstrated an improved Yb-doped hot injection strategy, successfully prepared a Yb-doped CsPbBrI2 NC in EVA composite film (CsPbBrI2 NCs/ECF), and improved the PLQY of the prepared CsPbBrI2 NCs/ECF. Furthermore, this work studied the application of CsPbX3 NCs/ECF in the field of backlight displays. The results show that CsPbX3 NCs/ECF has a wide color gamut, which reaches 119.9% of the National Television Standards Committee 1953 standard color gamut and 89.2% of the Rec. 2020 standard color gamut.