High-Efficiency Narrow-Band Green-Emitting Manganese(II) Halide for Multifunctional Applications

Abstract

Zero-dimensional (0D) Mn²⁺-based metal halides used as luminescent materials and scintillators have become a research hotspot in the field of photoelectric materials and devices due to their unique composition, structure, and fluorescence properties. It is of great value to explore new Mn²⁺-based metal halides to achieve multifunctional applications. Herein, the novel 0D Mn²⁺-based metal halide single crystal (BPTP)₂MnBr₄ is synthesized by a simple solvent-antisolvent recrystallization method. Under excitation at 468 nm, the (BPTP)₂MnBr₄ single crystal shows a pronounced narrow-band green luminescence centered at 515 nm derived from the <i>d</i>-<i>d</i> transition of the Mn²⁺ ion. This emission has a relatively narrow full width at half maximum of 43 nm and a high photoluminescence quantum yield (PLQY) of 82%. In addition, (BPTP)₂MnBr₄ exhibits good thermal stability at 393 K with a retention of 79% of the initial photoluminescence intensity at 298 K. Benefiting from its strong blue light excitation, high PLQY, and good thermal stability, we manufacture an ideal white light-emitting diode (LED) device using a 460 nm blue LED chip, green-emitting (BPTP)₂MnBr₄, and commercial K₂SiF₆:Mn⁴⁺ red phosphor. Under 20 mA drive current, the LED shows a high luminous efficiency of 112 lm/W and a wide color gamut of 110.8%, according to the National Television System Committee standard. In addition, (BPTP)₂MnBr₄ crystals show a strong X-ray absorption. Based on the commercial Lu₃Al₅O₁₂:Ce³⁺ scintillator, the calculated light yield of (BPTP)₂MnBr₄ reaches up to about 136,000 photons/MeV and the detection limit reaches 0.282 μGy_air s^-1. Additionally, a melt quenching approach is used to construct a (BPTP)₂MnBr₄ clear glass scintillation screen, realizing a spatial resolution of 10.1 lp/mm. The proper performances of (BPTP)₂MnBr₄ as phosphor-converted LED materials and the X-ray scintillator with the addition of eco-friendly, low-cost solution processability make 0D Mn²⁺-based metal halides potential luminescent materials for multifunctional applications.