Characterizations of white-light ZnWO4 phosphor prepared by blending complementary phosphor

Abstract

In the preparation of ZnWO4 phosphor, crystalline ZnWO4 was created, even though the concentration of WO3 was only 10 mol%. ZnWO4 was the dominant crystallization phase when the concentration of WO3 exceeded 40 mol%. The optimal crystallization of ZnWO4 phosphor was obtained when the composition molar ratio of ZnO to WO3 was 1:1, and sintering was carried out at 1,100°C for 3 h. In this condition, a bluish-green emission with a peak at 460 nm was observed. For Y2O3:Eu3+,Li+, the complementary phosphor of ZnWO4, the Li flux improved phosphor crystallization. The red emission peak of the Y2O3:Eu3+,Li+ phosphor was measured at about 612 nm. The optimal photoluminescence intensity of the Y2O3:Eu3+,Li+ phosphor was obtained when it was sintered at 1,200°C for 5 h and was mixed with 11 mol% Eu2O3 and 70 mol% Li2CO3. When the weight ratio of Y2O3:Eu3+,Li+ to ZnWO4 was 1:4, the Y2O3:Eu3+,Li+-blended ZnWO4 phosphor showed white-light emission with Commission Internationale de l’Eclairage coordinates at (0.34, 0.30). The luminance of the white-light phosphor excited by a 6-W UV lamp was around 160 cd/m2.