The Performance of Quartz Crystal Microbalance Coated TiO2-Porphyrin Nanocomposite Thin Film Gas Sensors

Quartz crystal microbalance (QCM) coated TiO2-porphyrin nanocomposite thin film gas sensors were fabricated to detect some volatile organic compounds namely ethanol, acetone, 2-propanol, cyclohexane, toluene and o-xylene. The QCM thin films were prepared by dipping the QCM into mixed sol-gel of TiO2 nanciparticles and 5,10,15,20-tetraphenyl-21H,23H-manganese (III) chloride. It was found that the thin films were sensitive towards the all type of organic vapors that indicated by a huge change in the QCM frequency upon exposure towards gases. The responses were found to be stable and reproducible. The sensitivity was found to depend on the mixture ratio between TiO2. and porphyrin. We also found that the sensitivity was depending on the surface microstructure of the thin films. The gas thin film interaction mechanism is proposed.