Effect of synthesis conditions on morphology and spectral properties of SiO2:DAST composites

SiO2:DAST composites based on SiO2 matrices with a porosity of 30-70% saturated with DAST molecules were synthesized both by evaporation from a solution and by lowering the temperature in a crystallizer. X-ray study of the composites showed the absence of DAST crystalline phase. There was only one luminescence band for all the composites with a maximum in the region of 620-640 nm (at their annealing at 100 degrees C). A hypsochromic shift (590-565 nm) of the luminescence band maxima of the composites was observed with an increase in their annealing temperature to 200 degrees C. Annealing at 200 degrees C also led to a change in the structure of the composite - filling of the pores of SiO2 matrices. This was probably due to a decrease in the interaction of the adsorbed DAST cations with the surface of SiO2 matrices due to exfoliation of DAST layers from the xerogel surface into the pores.

Automated summary

SiO2:DAST composites with a porosity of 30-70% were synthesized using evaporation from a solution and temperature lowering methods. X-ray analysis revealed the absence of DAST crystalline phase in the composites. The composites exhibited a single luminescence band with a peak at 620-640 nm after annealing at 100 degrees C. Increasing the annealing temperature to 200 degrees C resulted in a hypsochromic shift of the luminescence band maxima to 590-565 nm and a change in the structure of the composite, including the filling of SiO2 matrix pores due to exfoliation of DAST layers.