Silica-titania nanocomposite based fiber optic sensor for aromatic hydrocarbons detection

Surface stability of deposited sensing material is becoming a crucial issue in the field of opto-chemical sensor technology due to cracks/stresses. Porous silica-titania (ST) nanocomposite coating material is synthesized and doped with CdTe as transducers for sensing cyclic compounds. Ultra-thin coatings are obtained, ∼11 nm for ST nanocomposite, and 5 nm for encapsulated and heat-treated samples. BET analysis shows large surface area ∼441 m2/g ± 3 m2/g and pore diameter 58 Å of ST nanocomposite. It decreases down to ∼410 m2/g ± 2 m2/g, and pore diameter to 24 Å, after encapsulation. However, after heat treatment, it again increases up to 419 m2/g ± 2 m2/g and pore diameter to 38 Å. The sensitivity of 71.37 counts per unit change in the carbon chain with correlation determination coefficient R2 ∼0.89 at 468 nm is observed. The prepared sensor device shows excellent stability, signal-to-noise ratio, and good reversibility towards different hydrocarbons and non-hydrocarbons (inorganic materials).