Tunable luminescence and improved thermostability via Tm―Dy energy transfer in a tellurooxyphosphate phosphor

Currently, to solve the restrictions of multiple phosphors-converted white light-emitting diodes (w-LED) such as reabsorption and fabricating cost, the single-phase white-emitting phosphor-based w-LED stands a good chance. In this work, we present a type of color-tunable barium tellurooxyphosphate-based phosphor Ba2TeP2O9 (BTP):Tm3+,Dy3+. Under 362 nm excitation, the emitting white color adjustment is realized due to the efficient Tm3+→Dy3+energy transfer. The energy transfer mechanism is ascribed to the dipole-dipole interaction with the 93.3% efficiency. Moreover, the synergistic effect of the Dy3+→Tm3+back-energy transfer and high Debye temperature contributes to the improvement of the luminescent thermostability. For the representative BTP:0.04Tm3+,0.06Dy3+phosphor, the emission at 423 K has only the intensity loss of 9.3%, relative to the initial value, and the chromaticity shifting level is 12.9 × 10–3, verifying that it has comparable luminescence thermostability to the commercial products (such as CaAlSiN3:Eu2+ and BaMgAl10O17:Eu2+). The BTP:0.04Tm3+,0.06Dy3+-based w-LED exhibits the satisfactory parameters of high Ra (88) and low CCT (3227 K). Our work illustrates an effective energy transfer path between Tm3+and Dy3+for developing white-emitting phosphors with high thermostability for lighting application.