Down-Shifting in the YAM: Ce + Yb System for Solar Cells.

In this work, we investigate Ce to Yb energy transfer in YAlO (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 and Yb with varying concentrations are presented, and the Ce to Yb energy transfer is proven. Measurement of highly non-exponential luminescence decays of Ce 5d band allowed for the calculation of maximal theoretical quantum efficiency, of the expected down-conversion process, equal to 123%.

Blue emissions in Dy3+ doped Y4Al2O9 crystals for temperature sensing.

Temperature dependent emission spectra and decay times of trivalent dysprosium (Dy3) activated Y4Al2O9 (YAM) crystals have been studied for the first time (to our knowledge). The ratio of emission lines intensity can be used in temperature measurements, as it is not dependent on the variability of absolute intensity. The Boltzmann model was applied for modeling the temperature variation of the 4I15/2 and 4F9/2 states emissions relative intensities 455 and 481 nm, respectively.