Spectroscopic analysis of dye-silica core-shell nanoparticles (DSCSNPs)

Absorption and Fluorescence spectra of DSCSNPs are investigated at different concentrations, it was found that the shapes of the absorption and fluorescence spectra remained the same irrespective of an increase in the concentration, the absorption and fluorescence wavelengths peaks are located around 365nm and 440nm respectively. The intensities of DSCSNPs were observed to be greater than that of free C445 dye. Aging effects on fluorescence spectra of free C445 dye, dye-silane and DSCSNPs are studied after upon one month of preparation the samples. The results showed that the aging degradation slope of free C445 dye is more than seven times greater than that of DSCSNPs and the aging degradation slope of dye-silane is more than three times greater than that of DSCSNPs, so DSCSNPs seems to be more stable than free C445 dye and dye-silane. DSCSNPs showed severe photobleaching, presumably due to the penetration of amount of aerial oxygen molecules through the porous silica shell that caused photodegradation of majority of dye molecules, however, DSCSNPs showed better photostability than free dye.