Energy transfer and white luminescence in Bi3+/Eu3+ co-doped oxide glasses

Abstract

Bi3+/Eu3+-doped SiO2–Al2O3–CaO–B2O3–La2O3–K2O glasses were fabricated and the luminescent properties, energy transfer as well as thermal stability were systematically investigated. Under 333 nm light excitation, bluish-green luminescence centered at 480 nm is observed in the obtained Bi3+-doped glass. By co-doped with Eu3+, highly efficient energy transfer process happens from Bi3+ to Eu3+ via a quadrupole-quadrupole interaction. The energy transfer efficiency can reach 86% and the concentration of Eu3+ is not quenched in here. With increasing Eu3+ concentration, tunable luminescence from bluish-green via white to orange-red is realized. Significantly, pure white light emission with CIE coordinates (0.348, 0.333) is obtained when excited by 333 nm light. Temperature-dependent emission spectra present superior color stability in operating temperature lower than 423 K for the prepared glasses. These results indicate that these glasses are potential white light emitting materials for organic-resin-free W-LEDs.