Influence of coordination environment and dielectric contrast on the spectral-luminescent properties of europium ions in the pores of film opals

Abstract

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 Eu^{3+ 5}D₀→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→⁷F_J (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.