Optical properties of poly(methyl methacrylate)–titania nanostructure thin films containing ellipsoid-shaped titania nanoparticles from ex-situ sol-gel method at low growth temperature

This paper reports on the linear and nonlinear optical responses of the PMMA-TiO₂ nanohybrid thin films which are synthesized by a flexible ex-situ sol-gel/polymerization process, assisted by spin coating and multi-step baking. Triethanolamine (TEOA) as surfactant and shape controller is used to modify the interface between PMMA and TiO₂, allowing a highly homogeneous dispersion of the ellipsoid-shaped TiO₂ nanoparticles. The resulting nanohybrid thin films have highly optical transparency as proved by the linear absorption photon-energy spectra and indicate an enhanced nonlinear optical (NLO) response as confirmed by the Z-scan technique using 800-nm, 120-femtosecond (fs) laser pulses, highlighting the potential of the nanocomposites for efficient optical devices.