Preparation and luminescence properties of K2TiF6:Mn4+narrow-band red phosphor
Based on the coprecipitation and cation exchange method,narrow-band K2TiF6∶Mn4 red phosphor was prepared by a HF-free liquid phase method.The effects of the ammonium fluoride and sulfuric acid(NH4F+H2SO4)reactant dosage and the doping concentration of Mn4+on the morphology and luminescent properties of the samples were studied.A white light-emitting diode(WLED)was packaged using the synthesized K2TiF6∶Mn4+with commercial Y3Al5O12∶Ce3+and InGaN blue chips.The results showed that the prepared K2TiF6∶Mn4+red phosphor had strong UV and blue absorption at～360nm and-465nm,and presented sharp emission peaks in the wavelength range of 600-650 nm.With the increase of the NH4F+H2SO4 dosage,the luminous intensity of the phosphor first increased and then decreased,and the sample showed concentration quenching effect when the doping concentration of Mn1+was 10％.When the dosage of NH4F+H2SO4 was 60mmol and the doping concentration of Mn4+was 8％,the optimal quantum efficiency of the prepared phosphor sample reached 67％,and the WLED device packaged with it achieved a color rendering index of 79.4 and a lumen efficiency of 80.62 lm/W.
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