Ba3LaNa(PO4)3F:Tm3+, Dy3+: A tunable blue-white color emitting phosphor via energy transfer for UV white LEDs

A series of Tm3+/Dy3+ co-doped Ba3LaNa(PO4)3F (BLNPF) phosphors were synthesized successfully via a high-temperature solid-reaction, and luminescence properties were investigated. Upon near violet excitation, BLNPF:Tm3+, Dy3+ phosphors exhibit Tm3+:1D2-3F4 and Dy3+:4F9/2-6HJ (J⬰=⬰15/2, 13/2, 11/2) transitions with different luminescence intensity. The emitting color of the obtained products was found to shift from blue to white as a result of efficient energy transfer (ET) from Tm3+ to Dy3+ ions. According to photoluminescence emission intensity, the positive effect of activator on ET efficiency was calculated and the maximum ET efficiency was found around 72.6% with Dy3+ concentration was 0.04. By means of Dexter⬢s theoretical model, furthermore, dipole-dipole interaction was confirmed as the mechanism of energy transfer from Tm3+ to Dy3+ ions. The results suggested that BLNPF:Tm3+, Dy3+ phosphor might be a promising single-phased white-light-emitting phosphor for UV white-light LED.