The use of a single ammonium acidic salt towards simple green co-precipitation synthesis for Mn4+-activated fluorides

摘要

Herein, a simple green co-precipitation route for Me4+-activated fluorides has been realized via individually using the aqueous acidic salt NH4HF2 as a solvent. The systematic explorations of ionization, erosion, solvent concentration, solvency on reactants, and reaction with an extra weak acid disclosed that the near-saturated aqueous NH4HF2, ionizing into abundant HF2-, H+ and F- ions, exhibited large dissolving capacity and good stabilization on Mn4+ without obvious toxicity. The green synthesized example of Cs2GeF6:Mn4+ emitted a typical narrow band red light at 633 nm with normal optimal doping at similar to 8 at%. Compared with its contrast prepared from the HF system, it experienced only similar to 10% reduction in quantum efficiency and slight emission attenuation below 150 degrees C as the more humidity-sensitive weaker acid surface aroused lattice thermal vibration. The further action as red component fabricated a high-quality warm white light-emitting diode (W-LED) with a high color rendering index (Ra similar to 91), high luminous efficacy (similar to 149 lm W-1), low correlated color temperature (similar to 3211 K), and good color stability against the operating environment. Combined with the universal synthesis of A(2)XF(6):Mn4+ (A = K, Rb, Cs; X = Si, Ge), our findings can probably open up a simple and feasible green synthetic strategy for efficient Mn4+-doped fluorides using acidic salts.

关键词