Fabrication, structural evaluation, optical and photoelectrochemical properties of soft lithography based 1D/2D surface patterned indium titanium oxide sol-gel thin film

TLDR: In this paper, a mesoporous indium titanium oxide (INTO) sol-gel-based thin film was fabricated on glass by soft lithography, where the surface patterns over amorphous thin film surfaces were performed by atomic force and transmission electron microscopes as well as X-ray diffraction study.

Abstract: For the first time, we report on successful fabrication of 1-dimensional (1D) nanoprism and 2-dimensional (2D) nanocone shaped surface patterned amorphous indium titanium oxide (INTO) sol-gel based mesoporous thin films on glass by soft lithography. Structural evaluation of the surface patterns over amorphous thin film surfaces was performed by atomic force and transmission electron microscopes as well as X-ray diffraction study. Chemical bonding/oxidation state of constituent elements in INTO film matrix was analyzed by FTIR and X-ray photoelectron spectroscopies. Maximum optical absorption and minimum specular surface reflection in visible region were noticed in 2D patterned film. The thin film with physical thickness over 100 nm was mesoporous in nature (~ 14% porosity) as measured by spectroscopic ellipsometer. A significant improvement in photoelectrochemical (PEC) activity was found in 2D patterned film under visible light that could be associated with the enhancement in light absorption/trapping by the periodic nanocones. Moreover, the existence of mesopores could provide excess active sites for electrolyte diffusion and mass transportation. Thus, the mesoporous 2D patterned thin film could have substantial opportunity in solar energy conversion. The facile technique could create an avenue for fabrication of complexed surface patterned thin films with improved PEC property.