Mn2+-Based narrow-band green-emitting Cs3MnBr5 phosphor and the performance optimization by Zn2+ alloying†
To discover new narrow-band green-emitting phosphors is a challenge for backlighting light-emitting diodes (LEDs) used in liquid crystal displays (LCDs). The synthesis and optical properties of Cs3MnBr5 are demonstrated herein. The intrinsic Mn2+ luminescence without concentration quenching leads to intense green emission at 520 nm with narrow full width at half maximum of 42 nm and high photoluminescence quantum yield (PLQY) of 49% under the excitation at 460 nm. When a small amount of Zn2+ is introduced into Cs3MnBr5, the luminescence intensity decreases slightly. However, the thermal stability of Cs3MnBr5 is improved from 82% to 87% with the intensity values at 423 K compared to that at 298 K. The white LED device fabricated using Cs3Mn0.96Zn0.04Br5 (green) and K2SiF6:Mn4+ (red) phosphors with a blue LED chip exhibit a high luminous efficiency (107.76 lm W−1) and wide color gamut (101% National Television System Committee standard (NTSC) in Commission Internationale de L’Eclairage (CIE) 1931 color space), demonstrating its potential application in wide color gamut LCD backlights.