Luminescence of Eu3+ and Sm3+ doped potassium tungstate phosphors

Abstract

The luminescent properties of Eu3+ and Sm3+ doped potassium tungstate phosphor were investigated. The K4-3x(WO 4)2:Eux,Smy phosphor was produced by firing the mixed precursors, followed by re-firing with a flux. The re-firing process provided the clean surface to the particles. The excitation spectra showed that the strong absorption in the region of ultra violet light occurred due to the high europium doping concentration. The incorporation of europium to potassium tungstate was easier, compared to other host materials. The excitation spectra could be controlled by the small addition of samarium. The increase of energy absorption around 405nm was assigned to the Sm3+ ions. The comparison between real x-ray diffraction and simulated one revealed that the crystal structure of K4-3x(WO4)2:Eu x,Smy phosphor is monoclinic with a space group, C2/c.