Down-Shifting in the YAM: Ce(3+) + Yb(3+) System for Solar Cells

In this work, we investigate Ce(3+) to Yb(3+) energy transfer in Y(4)Al(2)O(9) (YAM) for potential application in solar spectrum down-converting layers for photovoltaic devices. Photoluminescence properties set, of 10 samples, of the YAM host activated with Ce(3+) and Yb(3+) with varying concentrations are presented, and the Ce(3+) to Yb(3+) energy transfer is proven. Measurement of highly non-exponential luminescence decays of Ce(3+) 5d band allowed for the calculation of maximal theoretical quantum efficiency, of the expected down-conversion process, equal to 123%. Measurements of Yb(3+) emission intensity, in the function of excitation power, confirmed the predominantly single-photon downshifting character of Ce(3+) to Yb(3+) energy transfer. Favorable location of the Ce(3+) 5d bands in YAM makes this system a great candidate for down-converting, and down-shifting, luminescent layers for photovoltaics.