A zero-thermal-quenching and color-tunable phosphor LuVO4: Bi3+, Eu3+ for NUV LEDs

Thermal quenching is one of the most crucial challenges for LED phosphors, in which the phosphor in LED device suffers from emission loss due to non-radiative transition with increasing temperature. Here, we report a broadband-excited and color-tunable LuVO4: Bi3+, Eu3+ phosphor that does not exhibit thermal quenching even up to 200 degrees C. The phosphor shows Bi3+ absorption broadband ranging from 250 to 400 nm, along with the sensitized Eu3+ red emission lines. The emission color tuned from yellow with color coordinate (0.403, 0.507) to bright red (0.609, 0.370) as a function of Bi3+/Eu3+ ratio. The phenomenon of zero thermal quenching originates from enhanced energy transfer (ET) from Bi3+ 3P1 state to Eu3+ D-5(4) state through the population inversion from P-3(0) to P-3(1) at high temperature. Due to strong UV absorption, high quantum efficiency (-76%) and excellent thermal stability, the as-prepared LuVO4: Bi3+, Eu3+ phosphors can be potential candidates as red phosphors applied in UV-pumped LEDs.