Ultrasonically assisted synthesis of mesoporous TiO2 nanoparticle thin films via sol-gel process for chemo-resistive gas sensor applications

Micro electro-mechanical systems (MEMS) based chemo-resistive gas sensors often utilize metal oxides as the sensing layer. Nanoparticle based porous oxides provide the necessary high specific surface area to volume ratio for fabrication of highly sensitive gas sensors. However, synthesis and cost effective means of deposition of these nanoparticles remains a challenge for mass sensor production. In this paper we present the synthesis and characterization of mesoporous titanium dioxide (TiO₂) nanoparticle thin films based on ultrasonically assisted sol-gel process using titanium tetraisopropoxide (TTIP) as precursor. The developed sol has particulates of approximately 20 nm with pore sizes of 20 nm and a shelf life of over one year. The proposed method allows for deposition of crack free mesoporous, 110 nm thick, thin films using a simple spin coating process.