Silica/titania composite sol-gels doped with GO were investigated as possible reusable substrates for plasmon-free surface enhanced Raman spectroscopy (SERS). Sol-gels were prepared by the base-catalyzed hydrolysis of tetramethyl orthosilicate (TMOS) in the presence of GO, and titanium(IV) propoxide (TPOT) or titanium dioxide nanoparticles (P25). Sol-gels were transformed to aerogels via carbon dioxide supercritical fluid drying, and to xerogels by air-drying the sol-gels or by heating them in a tube furnace under a nitrogen atmosphere. The characteristic spectrum of GO was observed in the sol-gel materials with and without low titanium dioxide concentrations. The spectra of air-dried and thermally reduced xerogels was fitted with a two-Lorentzian peak fit using Origin 9 to gauge the defect density of GO inside of the sol-gels. The spectra of the reduced xerogels showed a shift of the position of the G peak to the right and a decrease in both the intensity of D’ and the I<sub>D</sub>/I<sub>G</sub> ratio, which is an expected consequence of graphitization, and it signals both a decrease in the oxygen content and an increase in the defect density. GO can be detected and reduced within silica/titania composite materials, thus, providing a stable surface for GO to promote charge transfer (CT) and enhance Raman scattering, which makes these GO-doped sol-gel materials potential candidates to be used as highly stable, reusable, biologically-compatible chemical sensors.

Investigation of silica/titania composite materials doped with graphene oxide (GO) as substrates for plasmon-free surface enhanced Raman spectroscopy and analysis of GO defect density after thermal reduction

255th National Meeting (2018)

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