Luminescence from the 5D1,2,3 excited states of Eu3+ in Y4Al2O9 crystal

The site-selective emission originating from 5D1,2,3 energy levels of Eu3+ in Y4Al2O9 (YAM) monoclinic bulk crystal is investigated. Energy and Stark splitting of excited states of europium in YAM are determined based on the low temperature absorption and emission spectra. Luminescence decays of three different sites of Eu3+ ions are measured as a function of temperature and europium concentration. The cross-relaxation among the Eu3+ ions are observed and discussed. Non-resonant mechanisms responsible for the temperature quenching of 5D1 emission are proposed.