Effects of alkali metal as charge compensator on the luminescence properties of ZnWO4: Eu3+ phosphors synthesized by solid-state reaction

Abstract

A series of ZnWO4:Eu3+, M+ (Li, Na, K) phosphors were prepared using a facile solid-state reaction method by sintering at 800 °C. The XRD patterns of the phosphors indicate that the Eu3+ and M+ ions have successfully been introduced into the ZnWO4 lattice. Their luminescent properties have been studied. The broad excitation peak from 280 to 315 nm by monitoring emission at 616 nm perfectly matches the wavelength range of deep UV LED based on AlGaN semiconductor. When the doping concentration of Eu3+ exceeds 2% in the ZnWO4: Eu3+, the luminescence intensity of Eu3+ gradually decreases due to the formation of impurity Eu2(WO)4. The alkali metals are added into the ZnWO4 as a charge compensator. After the introduction of alkali metals, emission spectra have changed obviously. The addition of Li+ can effectively promote the energy transfer from WO42− to Eu3+. The Commission Internationale de L'Eclairage (CIE) chromaticity color coordinates are calculated. The color of the emitting light can be tuned from greenish blue to white and finally to the red via co-doping different alkali metals.