Green-emitting phosphor Na2Gd2B2O7:Ce3+, Tb3+ for near-UV LEDs

Abstract

An intense green-emitting phosphor Na₂Gd₂B₂O₇:Ce³⁺, Tb³⁺ is developed on the basis of the highly efficient energy transfer from Ce³⁺ to Tb³⁺. The photoluminescence emission and excitation spectra, the lifetime, and the effect of Tb³⁺ concentration are investigated in detail. Results confirm the occurrence of non-radiative energy transfer from Ce³⁺ to Tb³⁺ with an efficiency of over 80%. The intensity ratio of blue emission from Ce³⁺ and green emission from Tb³⁺can be tuned by adjusting their concentrations. The enhanced photoluminescence of Tb³⁺ with sharp emission lines could be obtained by the broad band excitation peak at about 360 nm from the allowed 4f–5d absorption of Ce³⁺ ions. The results suggest that the phosphor Na₂Gd₂B₂O₇:0.05Ce³⁺, 0.12Tb³⁺ with the optimal composition could potentially be used for near ultraviolet light-emitting diodes (n-UV LEDs).