Time-resolved spectroscopy of Bi3+ centers in Y4Al2O9

Abstract Steady-state and time-resolved emission and excitation spectra as well as luminescence decay kinetics are studied at 4.2–400 K under excitation in the 3–6 eV energy range for Bi 3+ ions substituting for Y 3+ ions in four inequivalent crystal lattice sites of Y 4 Al 2 O 9 :Bi ceramics. Luminescence characteristics of Bi 3+ centers of all the four types are identified and are shown to arise from the radiative decay of the triplet relaxed excited state (RES) of Bi 3+ ions. The parameters of the triplet RES, namely, probabilities of the radiative and nonradiative transitions from the metastable and emitting levels as well as the energy distance between these levels, are determined. The influence of the nearest surroundings of Bi 3+ ions on the luminescence characteristics and the parameters of the triplet RES of Bi 3+ centers is discussed.