Abnormal Anti‐Quenching and Controllable Multi‐Transitions of Bi3+ Luminescence by Temperature in a Yellow‐Emitting LuVO4:Bi3+ Phosphor for UV‐Converted White LEDs

Phosphors with an efficient yellow‐emitting color play a crucial role in phosphor‐converted white LEDs (pc‐WLEDs), but popular yellow phosphors such as YAG:Ce or Eu²⁺‐doped (oxy)nitrides cannot smoothly meet this seemingly simple requirement due to their strong absorptions in the visible range. Herein, we report a novel yellow‐emitting LuVO₄:Bi³⁺ phosphor that can solve this shortcoming. The emission from LuVO₄:Bi³⁺ shows a peak at 576 nm with a quantum efficiency (QE) of up to 68 %, good resistance to thermal quenching (T_{50 %}=573 K), and no severe thermal degradation after heating–cooling cycles upon UV excitation. The yellow emission, as verified by X‐ray photoelectron spectra (XPS), originates from the (³P₀,³P₁)→¹S₀ transitions of Bi³⁺. Increasing the temperature from 10 to 300 K produces a temperature‐dependent energy‐transfer process between VO₄^3? groups and Bi³⁺, and further heating of the samples to 573 K intensifies the emission. However, it subsequently weakens, accompanied by blueshifts of the emission peaks. This abnormal anti‐thermal quenching can be ascribed to temperature‐dependent energy transfer from VO₄^3? groups to Bi³⁺, a population redistribution between the excited states of ³P₀ and ³P₁ upon thermal stimulation, and discharge of electrons trapped in defects with a trap depth of 359 K. Device fabrication with the as‐prepared phosphor LuVO₄:Bi³⁺ has proved that it can act as a good yellow phosphor for pc‐WLEDs.