Double coating strategy simultaneously enhances emission, fluorescent thermal stability and water resistance of K2SiF6:Mn4+ phosphor

In this paper, K2SiF6:Mn4+@GQDs 6 mg/mol@0.10K2SiF6 (the optimal sample, K2SiF6 = KSF, GQDs = NH3- contained graphene quantum dots) with excellent emission intensity, water resistance and thermal stability was synthesized by double coating strategy. The detail outcomes are as follows: (a) The emission intensity of phosphors are enhanced by the coating with GQDs and KSF. (b) The water resistance of the phosphors is slightly enhanced by coating with GQDs and greatly increased by coating with KSF due to the effective isolation of [MnF6](2-)from water by the coating layer. (c) The NTQE (negative thermal quenching effect) of the samples is enhanced by the coating with GQDs and KSF. The strong NTQE mechanism is assigned to the increased electron -phonon interactions caused by the double coating. A WLED prototype with excellent performance (Ra = 88.4, CCT = 3725 K) at 20 mA drive current was assembled from the optimal sample, showing that it can be widely applications in WLED field.