Study of Concentration Quenching and Energy Transfer Mechanism in Ce Doped Y2O3 Nanomaterials.

Abstract

We study concentration quenching and energy transfer mechanisms of yttrium oxide (Y2O3) nanomaterials doped with different concentrations (0-5mol%) of cerium (Ce). Photoluminescence (PL) spectra recorded under an excitation wavelength of 350nm show a broad emission band at ∼ 406nm and a feeble emission band at ∼ 463nm in the undoped Y2O3 sample. The doping of Ce in Y2O3 induced multiple PL peaks within the blue-green region of the spectrum in all the doped samples with the peak at ∼ 466nm being notably the prominent one. This prominent emission band exhibits a decrease in intensity with increasing Ce concentration due to concentration quenching. Analysis of Time-resolved photoluminescence (TRPL) spectra reveal that the average emission lifetime of Ce-doped Y2O3 is shorter than that of the undoped Y2O3 sample. The concentration quenching effect and the decrease of average emission lifetime of the dominant emission band are explained on the basis of energy transfer from the host Y2O3 to the Ce3+ ion centres. The critical quenching concentration of Ce3+ ion in Y2O3:Ce phosphor was identified to be 1mol% and the critical transfer distance was estimated to be 23.74 Å. Analysis reveal that the concentration quenching mechanism involves nearest-neighbour interaction.