Performance of Quartz Crystal Microbalance gas sensors using thin films of titanium dioxide, porphyrin and titanium dioxide coated with dye porphyrin

Titanium dioxide (TiO2), porphyrin and TiO2 coated with dye porphyrin thin films were prepared on Quartz Crystal Microbalance (QCM) using sol-gel dip coating method and were tested for sensing of volatile organic compounds (VOCs). The porphyrin used was 5,10,15,20-tetraphenyl-21H,23H-porphine manganese (III) chloride (MnTPPCl). The sensing sensitivity was based on the change in the fundamental frequency of the QCM upon exposure towards six vapor samples, namely ethanol, acetone, cyclohexane, toluene, o-xylene and 2-propanol. It was found that all the thin films were sensitive towards all the vapors. However the TiO2 coated MnTPPCl thin film exhibit the most sensitive and has good selectivity property.