Structural elucidation by Raman spectroscopy and analysis of luminescence quenching by the Inokuti-Hirayama model in the Pr3+doped multi-component silicate photonic films

Thin films of multi-component silica glasses doped with Ca2+ and Pr3+ modifiers were fabricated by the spin coating technique. Surface micrographic images extracted by the Field Emission Scanning Electron Microscope revealed a homogeneous texture of the films. Detailed structural analysis by Fourier Transform Raman spectroscopy confirmed the existence of Si-O-Si and polyphosphate groups in the glass matrix. The Burstein-Moss shift was evidenced with doping, by an increase in the band gap of the glass films, evaluated by Tauc's plots. The films exhibit red and near infra-red emissions (NIR), corresponding to the transitions: 3P0 -> 3F2 and 3P0 -> 3F4 respectively. The decay analysis by the Inokuti-Hirayama (I-H) model validated the contributions of multi-polar interactions particularly that of dipole-quadrupole mechanisms, leading to significant quenching in the highly doped film. The energy transfer efficiency between the sensitizer and activator ions, determined by the formulations of the model was 51.8 %. The decreasing lifetime of the metastable state observed in the glass films could be considered to be prospective for NIR waveguide lasers and red laser sources for optical display screens.