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

Abstract 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.