Composite materials based on nanoporous SiO2 matrices and squarylium dye

• Sol–gel SiO2 matrices with different contents of HF acid were synthesized.
• The structure of SiO2 matrices was found to contain 5–12 nm and 60–600 nm pores.
• The size of the large pores increases with the concentration of HF acid.
• The composite material (SiO2: squarylium dye: methylmethacrylate) was obtained.
• The surface condition of the xerogel influences the spectral properties of the dye.

Sol–gel SiO2 matrices with different contents of HF acid were synthesized. The matrices were annealed at 600 °C and impregnated with squarylium dye SqD1 in methylmethacrylate (MMA) solvent. Xerogel nanoporous structure of SiO2 matrices was found to contain 5–12 nm and 60–600 nm pores. The size of large pores increases with the concentration of HF acid. For the synthesis of SiO2 matrices the ratio n(HF/TEOS) = 0.25–0.38 is the most optimal. At other HF concentrations the formed matrices are prone to cracking at drying, annealing and impregnation with the dye solution in MMA. The location of the maxima of the absorption and luminescence bands of SqD1 dye in the composite SiO2:SqD1:ММА is found to be influenced by the surface state of SiO2 xerogel depending on the concentration of HF acid at the synthesis of the matrices.