Sensitisation of Pr3+ in Y4Al2O9:Ce3++Pr3+ system for down-conversion of solar spectrum

In this work we analyse spectroscopic features and energy transfer mechanisms in the YAM: Ce3++Pr3+ system. Absorption spectra of the YAM: Ce3+ samples were measured, revealing absorption bands in the range of 300-400 nm allowing for relatively efficient absorption of the solar radiation. Measured excitation and emission spectra indicate the existence of energy transfer from Ce3+ to Pr3+. Cerium photoluminescence decay times of 5d emission were measured and energy transfer efficiency reached 16.86% for the best sample containing 0.5% Ce3+ and 1% Pr3+. Spectral properties were investigated to establish nature of this transfer, particularly whether it occurs to the 3P0 or 1D2 level or both. While we proved the existence of transfer to 3P0 level emission from 1D2 was also observed. Energy transfer from Ce3+ 5d bands to the 3PJ multiplet is necessary to enable further transfer to two Yb3+ ions in down-conversion process in prospective Ce3++Pr3++Yb3+ system.