Dynamics of resonance energy transfer process from Tb3+ to Eu3+ in Ga2O3 phosphor

Highlights: • Dynamics of resonance energy transfer process in β-Ga₂O₃:Tb, Eu was investigated. • Time-resolved PL curves are reproduced by calculations based on rate equation model. • Energy transfer rate, efficiency, and fraction of the number of indirectly excited Eu. • Energy transfer parameters are dependent on Eu doping concentration. -- Abstract: We investigated the dynamics of resonance energy transfer process in β-Ga₂O₃:Tb³⁺, Eu³⁺ phosphor by analyzing time-resolved photoluminescence (PL) spectra of Eu³⁺. The intensity rising of the PL curve was observed in the time (t) range of t < 0.3 ms by the excitation at 355 nm light. The time-resolved PL curves are well reproduced by theoretical calculations based on a rate equation model including direct excitation (pumping laser) and indirect excitation (energy transfer) processes of Eu³⁺. From the theoretical calculation, we estimated the energy transfer rate, the energy transfer efficiency, and the fraction of the number of indirectly excited Eu³⁺ due to the energy transfer from Tb³⁺ and found that these parameters are strongly dependent on Eu³⁺ doping concentration.