Enhancing Optical Properties of Zn‐Mn Solid Solution Hybrid Halides for Wide Color Gamut Backlight Displays

Hybrid metal halides display a range of optical properties and hold promise for various applications such as solid‐state lighting, anti‐counterfeiting measures, backlight displays, and X‐ray detection. The incorporation of zinc into (C 13 H 26 N) 2 MnBr 4 aims to enhance its structural rigidity and improve its narrow band green light emission properties. The resulting (C 13 H 26 N) 2 ZnBr 4 compound exhibits an identical crystal structure to (C 13 H 26 N) 2 MnBr 4 , indicating the potential for a solid solution of varying Zn and Mn ratios within this structural framework. (C 13 H 26 N) 2 Zn 0.2 Mn 0.8 Br 4 exhibits significantly enhanced properties, including a photoluminescence quantum yield of 92%, a minimum full width at half maximum of 43 nm, and 85% retention of room temperature emission at 420 K. Additionally, crystals of (C 13 H 26 N) 2 ZnCl 4 and (C 7 H 18 N) 2 ZnX 4 (X = Br, I) are synthesized, with (C 7 H 18 N) 2 ZnBr 4 displaying luminescent color changes dependent on excitation. (C 7 H 18 N) 2 Zn 0.2 Mn 0.8 Br 4 demonstrates reversible phase transitions and alterations in optical properties. A white light‐emitting diode utilizing (C 13 H 26 N) 2 Zn 0.2 Mn 0.8 Br 4 and commercial phosphors exhibited a color gamut of 112.2% of the National Television Standards Committee 1931 Standard. This investigation introduces a stable and highly efficient narrow‐band green phosphor suitable for displays.