Significantly improved photoluminescence of the green-emitting β-sialon:Eu2+ phosphor via surface coating of TiO2

Abstract

The β-sialon:Eu2+ phosphor particles were successfully coated by TiO2 nanoparticles via the sol-gel method. The TiO2-coated β-sialon:Eu2+ phosphor had a significantly improved photoluminescence (PL) performance under the 365 nm excitation, due to the localized surface plasmon resonance (LSPR) at the interface between the TiO2 coating layer and phosphor surface. The emission intensity of the TiO2-coated β-sialon:Eu2+ prepared with the titanium (IV) tetrabutoxide (Ti(OC4H9)4, TTBO):H2O = 1:0.5 volume ratio was dramatically increased by ~24%. When the preparation temperature was 500°C, it was responsible for superior PL intensity by considering the important domination factors of higher anatase content and spherical particle shape of the TiO2 coating layer to the LSPR effect. The coating around the phosphor surface by the TiO2 nanoparticles would be an effective technique to improve the PL efficiency of phosphor for the application in the white light-emitting diodes (LEDs), by utilizing the LSPR effect of the semiconductor coating layer, instead of conventional metal plasmonic materials.