Photoluminescence and excited state structure in Bi3+-doped Y2SiO5 single crystalline films

Single crystalline films of Bi-doped Y2SiO5 are studied at 4.2-350 K by the time-resolved luminescence methods under excitation in the 3.8-6.2 eV energy range. Ultraviolet luminescence of Y2SiO5:Bi (≈3.6 eV) is shown to arise from the radiative decay of the metastable and radiative minima of the triplet relaxed excited state (RES) of Bi3+ centers which are related to the 3P0 and 3P1 levels of a free Bi3+ ion, respectively. The lowest-energy excitation band of this emission, located at ≈4.5 eV, is assigned to the 1S0 → 3P1 transitions of a free Bi3+ ion. The phenomenological model is proposed to describe the excited-state dynamics of Bi3+ centers in Y2SiO5:Bi, and parameters of the triplet RES are determined.