Sensitization of Gd3+ and the dynamics of quantum splitting in GdF3:Pr,Eu

Efforts are reported to sensitize the Gd3+ excitation with Pr3+ for application to quantum cutting in GdF3 doped with Eu3+ and Pr3+. Excitation and emission spectra are reported for several samples with different concentrations of Eu3+ and Pr3+ at room temperature. In addition, time-resolved measurements are performed to obtain the dynamics of the various excited states of Gd3+. Strong enhancement of the 5D0 Eu3+ emission is observed for excitation of 6G of Gd3+ relative to that for other Gd3+-excited states as expected for quantum cutting. While some enhancement of the J=0 Eu3+ emission is also observed for excitation into the Pr3+ 4f5d states, the maximum quantum yield is disappointing, falling far below the desired goal of 2. The time-resolved studies indicate that one reason for the ineffective quantum cutting is that the Pr3+→Gd3+ energy transfer occurs predominantly to the 6I state of Gd3+. Results on the 6I→6P relaxation and the Gd3+(6P7/2)→Eu3+ energy transfer are described.