The conductive blend of the poly (3,4-ethylene dioxythiophene) and polystyrene sulfonated acid (PEDOT-PSS) polymers doped with Methyl Red (MR) dye in the acid form were used as the basis for a chemiresistor sensor for detection of ethanol vapor.
This Au│Polymers-dye blend│Au device was manufactured by chemical vapor deposition and spin-coating, the first for deposition of the metal electrodes onto a glass substrate, and the second for preparation of the organic thin film forming ~1.0 mm² of active area. The electrical resistance dependence was found for ethanol vapor carried by nitrogen gas and in humidity,sensitivity at 1.15 for limit detection of 26.25 ppm analyte and an operating temperature of 25 °C. The sensing process is quickly reversible and shows very a low power consumption of 20 μW.
The thin film morphology of ~200 nm thickness was analyzed by Atomic Force Microscopy (AFM), where it was observed to have a peculiarly granulometric surface favorable to adsorption. This work indicates that PEDOT-PSS doped with MR dye to compose blend film shows good performance like resistive sensor.
Reference : Sensors 2010, 10(4), 2812-2820
