Combining laser ablation and sol-gel techniques for the synthesis of nanostructured organic-inorganic matrices

In this work we report a new and simple method that combines pulsed laser ablation in liquids (PLAL) and sol-gel techniques to obtain nanocomposite glasses and gelatins. Using this combination, we obtained two kinds of materials, bulk glasses on the one hand and gelatin films on the other hand. In the case of glasses, gold nanoparticles (Au-NPs) are generated by PLAL using an Au target submerged in a transparent liquid solution made previously with tetraethyl orthosilicate (TEOS) adding diluted hydrochloric acid as catalyzer. For gelatins, the same procedure is employed; however, in this case only commercial gelatin and tap water are used. We have found that a successful synthesis strongly depends on time and temperature since the viscosity of the gels increases with time. For the drying process the gels are sealed and stored at room temperature for several days. We identify the principal parameters that have to be considered in order to achieve a successful synthesis. The samples are characterized by UV-vis spectroscopy, HRTEM, ellipsometry and AFM microscopy. UV-vis spectra show a surface plasmon resonance band with its maximum at 540 nm indicating the presence of Au-NPs. HRTEM reveals crystalline Au-NPs with an average size of 20 nm. AFM measurements indicate that the glasses have a very smooth surface. In the case of gelatins, self-sustained, transparent, and pink flexible films are obtained. Despite having determined the principal parameters involved in the obtention of these materials, we emphasize that a lot of work remains to be done in order to optimize this novel method of synthesis.