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

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).