Effect of IDE Spacing on the Performance of ErGO Chemiresistive Humidity Sensor

This research demonstrates the effect of the use of different Aurum (Au) interdigitated electrode (IDE) spacing on the performance of electrochemically reduced graphene oxide (ERGO) humidity sensor via electrodeposition method. Electrochemically deposition (ECD) is regarded as a green route approach where it does not require capping reagents or surfactant agents in the graphene oxide (GO) reduction process as well as a simple and economical synthesis procedure. In this experiment, four Au with different spacing used were 5um, 10um, 100um and 200um. The synthesis procedure was set up with cyclic voltammetry window parameter at sweep potential range 0.05V (start) to 0.05V (stop), vertex potential between the range -0.4V (upper) and -1.1 (lower), scan rate 5mV/s and 10 cycles in the aqueous solution graphene oxide (GO) for each sample at the 40°C water bath temperature. The fabricated samples with reduced graphene oxide (RGO) deposited on the surface of IDE were characterized on its humidity performance based on the results obtained in the current measurement (I-t) on the different relative humidity (RH) 40%RH-90%RH at 0.2V potential applied based on sensitivity, response time and recovery time. Moreover, the electrochemical properties ERGO was investigated via electrochemical impedance spectroscopy (EIS) with FRA measurement set up at applied voltage 0.2V for each fabricated sample. As a finding, 5um electrode spacing produce a great humidity performance with higher sensitivity, higher response time as well as higher recovery time. Whereas, the electrochemical impedance spectroscopy measurement showed the shorten the spacing the greater the ionic conductivity at electrode-electrolyte interface due to their low charge transfer resistance.