Optical study of the matrix effect on the ESIPT mechanism of 3-HF doped sol-gel glass

In this work we report our preliminary results on the synthesis and characterization of the optical properties of 3-hydroxyflavone (3-HF) doped sol-gel derived glass, to be applied as a wavelength shifting medium in GaAs based near UV-VIS detectors in order to extend the device response down to 350 nm. As already reported by several authors, the intramolecular excited-state proton transfer process (ESIPT) in the 3-HF molecule is strongly affected by the chemical environment. For this reason the evolution of the emission features of the synthesized glasses was investigated by changing the chemical nature of precursor alkoxides used in the sol-gel process. The influence of chemical surroundings on the ESIPT process was studied by analysing the samples with fluorescence spectroscopy. FT-IR spectroscopy was performed in order to study the chemical interactions between the host matrix and the encapsulated dye molecule. The main result of this work is that the Stokes-shifted emission from the 3-HF tautomeric form is enhanced at increasing trifunctional alkoxide amount and at decreasing polarity of the non-hydrolizable groups.