Luminescent properties of Na3YSi3O9 doped with Eu3+ under UV–VUV excitation

The luminescent properties of Na3Y1−xSi3O9:xEu3+ (0.05 ≦ x ≦ 0.80) powder crystals were investigated in UV–VUV region. The Eu3+–O2− charge transfer band (CTB) was observed to be located at around 233 nm and the environmental parameter (he) was estimated to be about 0.730. The excitation spectrum monitoring the 613 nm red emission from Eu3+ ions reveals the host absorption band (HAB) to be around 145 nm. The calculated Commission Internationale de l’Eclairage (CIE) chromaticity coordinates indicate the emission by 233 nm rather than by 147 nm excitation has the better color purity and the possible mechanisms have been proposed. The Eu3+-emission showed high quenching concentration due to the isolated YO6 octahedra in the host and the small he for the Eu3+ ions and the optimum concentration was determined to be as high as x = 0.65 and 0.30 with 233 and 147 nm excitation, respectively.