High-color-purity red-emitting phosphors RE2WO6:Pr3+ (RE = Y, Gd) for blue LED

Abstract

Pr3+-doped RE2WO6 (RE = Y, Gd) phosphors in pure phase were synthesized via conventional solid–state reaction in air. Photoluminescence properties of those phosphors were investigated in detail. High-color-purity red emission originated from the 1D2 → 3H4, 3P0 → 3H6 and 3P0 → 3F2 transitions was observed in Pr3+-doped RE2WO6 (RE = Y, Gd) under 450 nm excitation. Fluorescence concentration quenching in Pr3+-doped Y2WO6 could be attributed to phonon-assisted cross-relaxation energy transfer between the Pr3+ ions. The Commission International de L'Eclairage (CIE) chromaticity coordinates of 0.5 at% Pr3+-doped Y2WO6 was observed to be (0.663, 0.337). However, the thermal quenching of Pr3+-doped Y2WO6 is relatively serious. By integrating this phosphor with commercial Ce3+:YAG and a 450 nm blue chip, a white LED with 5254 K correlated color temperature and high-color- rendering index (Ra = 81) was fabricated. The present work suggests that Pr3+-doped RE2WO6 (RE = Y, Gd) as pure red phosphors have a potential application in the blue-chip WLEDs.