A novel Eu3+-doped phosphor-in-glass for WLEDs and the effect of borophosphate matrix

Abstract

Phosphor-in-glass (PiG) is a potential color convertor for high power WLEDs. A novel glass matrix with advanced performance is still a challenge. Recently, Eu3+ doped glass matrix has attracted much consideration mainly due to its red compensation. A new borophosphate matrix to realize Eu3+ red light was designed in the Na2O-ZnO-P2O5-B2O3-Eu2O3 system. Meanwhile, a series of PiGs composed of different concentrations of Y3Al5O12:Ce phosphor and the matrix were also fabricated by re-sintering. The crystallization of Eu3+ based phosphate offers a novel red emission quenching apart from normal concentration quenching in the glass system. No direct energy transfer but only little reabsorption occurs between Eu3+ and Ce3+ ions. The Ce3+ concentration effect is obvious on the electroluminescent color. The optimized color rendering index of 79.7, the CIE coordinates near natural white and the range of CCT from 3943 to 6097 K were obtained for the packaged white light emitting diodes (WLEDs) together with the excellent CCT stability higher than about 97.5% and the quadruple thermal conductivity than that of silicon resin. The work implies borophosphate glass based PiGs with fine transparence and energy conversion efficiency are promising for excellent WLEDs, while the LED by using the PiG sample without any yellow phosphor doped is of high color purity and has a potential use as the 465 nm blue source.