Luminescence enhancing encapsulation for strontium aluminate phosphors with phosphate

SrAl₂O₄:Eu²⁺,Dy³⁺ phosphors are chemically unstable against water. An encapsulation on the phosphors by direct reactions between triethyl phosphate and strontium aluminate was reported in this paper. Powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectrometry (EDS), thermogravimetric (TG) analysis, water resistance measurements, and photoluminescence (PL) spectrophotometry were used to characterize the phosphors before and after encapsulation. Experimental results showed that products of encapsulation reactions under an appropriate condition were in shape of nano-films on the phosphors. These thin films could effectively enhance both water resistance and photoluminescence of the phosphors.