Effect of effluent gas composition on characteristics of graphene oxide film based relative humidity sensor

Nitrogen and synthetic air have been used as standard effluent gases in relative humidity (RH) sensing experiments, especially to characterise the dynamic sensing capabilities of RH sensors utilising graphene oxide (GO) as the sensing material. In the present work, we have used GO coated quartz crystal microbalance (QCM) as a tool to investigate the mass adsorption characteristics of samples subjected to multiple humidification-dehumidification cycles using N₂ or synthetic air as the effluent gas. We identified that the residual mass adsorbed and retained by the GO film is on average 71.6% higher when using N₂ in the initial humidification-dehumidification cycle and this subsequently impacted the hysteresis characteristics until the GO film saturated. To negate the impact of the effluent gas, the GO-based sample should be treated with multiple humidification and dehumidification cycles using either effluent gas.