Interdigitated electrode fabricated by integration of ink-jet printing with electroless plating and its application in gas sensor

A method for the fabrication of PEDOT–PSS film modified interdigitated electrode by integrating inkjet printing with electroless plating technique is reported. Palladium nanoparticles stabilized in water by styrene-N-isopropylacrylamide oligomer (St-co-NIPAAm) are inkjet printed onto a flexible PET surface to create the catalytic sites, onto which nickel is subsequently deposited by an electroless plating method to obtain the desired interdigitated electrode pattern. As a first step the influence of the electroless plating conditions (plating temperature, plating time and stabilizer concentration) to prepare the interdigitated electrode are investigated. Then, a galvanic displacement reaction is utilized to deposit a monolayer of gold coating on the nickel film surface to increase the electrical conductivity. Finally a layer of PEDOT–PSS thin film is inkjet-printed on top of the gold interdigitated electrode and used as the sensor to detect CO2. The device is exposed to CO2 gas at concentration of 100 ppm at room temperature (300 K) and the obtained results are presented. Based on our proposed mechanism for the CO2 sensing, the PEDOT–PSS modified interdigitated electrode has good potential as a novel sensor for polar gases and vapors.