Resonant Frequency Tuning Technique for Selective Detection of Alcohols by TiO2 Nanorod-Based Capacitive Device

摘要: Selective detection of vapor species, especially belonging to the same group, is a crucial bottleneck for resistive sensor devices. In this paper, methanol, ethanol, and 2-propanol by Pd/TiO2 nanorod array/Ti device in capacitive mode was achieved, with improved selectivity, employing resonant frequency tuning technique. The optimal response obtained identifying over range 0.01–200 kHz. imaginary part impedance (−| Z | sinθ as function frequency) air alcohols revealed shift towards lower regime upon exposure alcohols. Moreover, difference frequencies (Δ f ) from one alcohol another were found be almost constant which facilitated frequency-selective sensing even varying concentrations target species (1, 50, 100 ppm present case). Such selective nature possibly originated different degree polarization molecules at duly correlated corresponding equivalent circuit model. However, real detection, when unknown, proposed does not work properly an array devices necessary.