Influence of Pressure on 5d →4f Emission Transitions of Ce~3+

摘要

High pressure is used to tune the emission and band structure of the phosphors Ce~(3+):Lu_2S_3 and Ce~(3+):Lu_2SiO_5. A significant red shift of the broad 5d → 4f emission of Ce~(3+) was observed in both phosphors. In Ce~(3+):Lu_2S_3, we also observed a significant decrease in the emission intensity of Ce~(3+) and attribute the quenching to a pressure-induced electronic crossover of the Lu_2S_3 conduction bandedge with the emitting 5d state of Ce~(3+). In Ce~(3+):Lu_2SiO_5, two Ce~(3+) sites are present and we observed energy transfer from one site (Ce(2)) to the other (Ce(l)) at low pressure. At high pressure, the energy transfer ceases and emission is no longer observed from the Ce(l) site. We propose an exciton recombination model of the energy transfer process.