Luminescence behavior of the europium (III) complexes with hexafluoracetylacetonate in the ORMOSIL matrices

The luminescence behavior of the europium (Eu) complexes with hexafluoracetylacetonate (HFA:Eu3+ complexes) in the ORMOSIL matrices has been investigated. The steady-state excitation and emission spectra of the 1 mol.% EuCl3 and the 3 mol.% hexafluoracetylacetonate (HFA) co-doped gel were similar to that of the HFA:Eu3+ complexes powders which were synthesized in ethanol solution, which indicated that the HFA:Eu3+ complexes have been synthesized in the 1 mol.% EuCl3 and the 3 mol.% HFA co-doped gel. The time-resolved spectra of the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel exhibited the ligand-to-metal energy transfer process, which also confirmed the synthesis of the HFA:Eu3+ complexes in the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel. The decay curves of the luminescence 5D0 state obtained by monitoring the 5D0→7F2 emission line for the HFA:Eu3+ complexes powders and for the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel could both be fitted to a single-exponential fitting function. The temperature of heat treatment has significant influence on the luminescence behavior of the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel. The luminescence intensities of the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gel reached a maximum at approximately 110 °C and decreased gradually with increasing temperature. However, the 5D0 excited-state lifetimes of the Eu3+ ions in the 1 mol.% EuCl3 and 3 mol.% HFA co-doped gels increased gradually with increasing temperature.