Experiments and analysis of infrared quantum cutting luminescence phenomena of Ho3+/Yb3+ codoped nanophase oxyfluoride vitroceramics

The infrared quantum cutting phenomenon, which is an international hot research field, of Ho3+Yb3+: oxyfluoride vitroceramics (FOV) was studied in the present paper. It was found from the fluorescence spectroscopy experiments that the excitation spectrum of 973.0 nm fluorescence of Yb3+ ion is very similar to the absorption and excitation spectra of Ho3+ ion. It suggests that the energy transfer from Ho3+ ion to Yb3+ ion is very efficient. Then, all the possible important energy transfer passages were analyzed. It was found that the energy transfers {5G4(Ho3+)→5F5(Ho3+), 2F7/2(Yb3+)→2F5/2(Yb3+)} and {5F5(Ho3+)→5I7(Ho3+), 2F7/2(Yb3+)→2F5/2(Yb3+)} result in the effective two-photon quantum cutting 973.0 nm fluorescence of Yb3+ ion when 5G4 or 3K7 or the above energy level of Ho3+ ion are excited. Finally, the quantum efficiency ηQE,1%Yb=43.0%ηQE,1%Yb=43.0% and ηQE,5%Yb=171.7%ηQE,5%Yb=171.7% of two-photon quantum cutting was calculated for Ho(0.5)Yb(1):FOV and Ho(0.5)Yb(5):FOV respectively. This research would be beneficial for the enhancement of solar cell efficiency.