Upconversion luminescence of Tm3+/Ho3+/Yb3+ codoped tellurite glass used for white light emission

Tm3+/Ho3+/Yb3+ codoped tellurite glass (TeO2-ZnO-La2O3) was prepared by conventional melt-quenching method. The absorption spectra and upconversion spectra of the glass were measured, and the upconversion luminescence mechanism was analyzed. Intensive red (662 nm), green (546 nm) and blue (480 nm) emissions of the tellurite glass were simultaneously observed at room temperature under 975 nm LD excitation. Upconversion red luminescence are due to the energy transition of Tm3+ ion: 1G4→3F4 and Ho3+ ion: 5F5→5I8, while upconversion green and blue are the results of Ho3+ ion: 5S2→5I8 and Tm3+ ion: 5S2(5F4) →5I8, respectively. With the increasing of Yb3+ content and the pump power, upconversion luminescence are also enhanced. The white light close to the standard white light emission has been obtained by adjusting the concentration of rare earth doping. Our result has practical significance for developing high-quality white LED.