Environmental-Friendly Cs3MnxZn(1–x)Br5@PS Films Used for Wide Color Gamut Backlight Displays

In recent years, all-inorganic metal lead halide cesium perovskites (CsPbX3, X = Cl, Br, and I) have shown excellent luminescence performance in the field of wide color gamut backlight displays. However, Pb2+ in CsPbX3 easily leaks because of the unstable structure of CsPbX3, which seriously threatens human health. However, Mn-based metal halides (MHs) have unique environmentally friendly characteristics. In this work, Zn2+-doped Cs3MnBr5 MHs were successfully prepared, which exhibited highly efficient green emissions at 520–522 nm. Moreover, Cs3MnxZn(1–x)Br5 shows excellent stability at room temperature (25 °C) compared with Cs3MnBr5. More excitingly, when Cs3MnxZn(1–x)Br5 was encapsulated in a polystyrene (PS) polymer, Cs3MnxZn(1–x)Br5@PS showed better water, acid, daylight, and blue light stabilities. In addition, the backlight display device was designed based on different green–red ratios and thicknesses of Cs3MnxZn(1–x)Br5@K2SiF6:Mn4+@PS light conversion films, and the color gamut was over 109% of the NTSC 1953 standard, which is better than that of the reported WLED devices based on Mn-based MHs thus far. This work undoubtedly shows that Mn-based MHs have great application potential in wide color gamut backlight displays and provide a practicable route to fabricate nontoxic, low-cost, and high-performance liquid crystal displays.