Influence of coordination environment and dielectric contrast on the spectral-luminescent properties of europium ions in the pores of film opals
The photoluminescence spectra of the inorganic salt of europium C6H9EuO6 × H2O in the pores of film opals, with globule diameter D ≈ 300 nm on a glass substrate, were measured. In the measured spectra the radiative transitions in the energy spectrum of Eu3+ 5D0→7F0, 5D0→7F1, and 5D0→7F2 were observed at wavelength 580 nm, 592 nm and 617 nm, respectively. The presence in the luminescence spectra of the maximum possible number of components of the Stark structure of the 5D0→7FJ (J=1–2) transitions, equal to 2J+1, and the high intensity of the 5D0 → 7F0 transition indicate that the symmetry of the luminescence centers is low, not higher than C3. The dependence of the luminescence spectra on the additional impregnation of the samples with glycerol was established: smoothing of the Stark structure and broadening of the 5D0→7F2 band were observed, as well as a decrease in the ratio of integrated intensities I(5D0→ 7F2 ) / I(5D0 →7F1) from 3.6 to 1.9.