Ethanol sensing behaviour of sol–gel dip-coated TiO2 thin films

• The TiO2 thin films show a linear logarithmic response (r2 = 0.9796) towards ethanol at 30 °C.
• The minimum detection limit was determined to be 10 ppm.
• Minimum electrical resistance hysteresis was observed.
• The films show a selective, stable and reproducible response towards ethanol vapour.

The TiO2 nanoparticles were synthesized by sol–gel method initiating titanium isopropoxide–propanol mixture as a precursor solution. The obtained TiO2 nanoparticles were then deposited onto the glass substrate using dip-coating method under optimized conditions. The ethanol sensing behaviour of the prepared TiO2 thin film was studied by chemiresistive method at room temperature (∼30 °C). The nanoparticle of TiO2 as thin film formed exhibited good sensing response of 535% with response–recovery times of 5 s and 52 s, respectively, in the presence of 50 ppm of ethanol vapour. The effect of electrical resistance hysteresis was also discussed to emphasize the reversible nature of the TiO2 film.