Influence of the chemical composition of the porous matrix and sintering atmosphere on the luminescent properties of bismuth-containing composites

The spectral-optical and luminescence properties of bismuth-containing composite materials based on matrices of high-silica porous glasses are investigated. Luminescence spectra, luminescence excitation spectra, infrared transmission spectra (8000–4000 cm$^{-1}$) depending on the composition of different types of matrices and sintering atmosphere (nitrogen, argon) of bismuth-containing composite materials were examined. It was found that the samples of bismuth-containing composite materials are characterized by UV ($\lambda_{\mathrm{em}}$ = 350 nm), blue-green ($\lambda_{\mathrm{em}}$ = 410–550 nm) and orange-red ($\lambda_{\mathrm{em}}$ = 600–725 nm) luminescence due to the presence of various bismuth active centers. The analysis of the spectra obtained by near-infrared spectroscopy demonstrates the formation of Bi$^{2+}$ dimers of bismuth and bismuth active centers associated with silicon.