Varying sonication conditions to tailor surface morphology of GO thin films for enhanced gas sensing performance

Efficient and enhanced gas sensing especially at room temperature is the demand for contemporary industrial applications. This has been made possible due to a paradigm shift from semiconducting metal oxides to 2D materials including Graphene Oxide (GO) and reduced GO (RGO). GO and its derivatives have ushered in a revolution mainly because of their high surface to volume ratio and presence of various oxygen groups. Literature reports since 2010 indicate existence of investigations by many research groups wherein multiple approaches have been employed to enhance the gas sensing capabilities of GO and RGO. Some of the more radical approaches have been fabrication of free standing GO films, adoption of green fabrication techniques, thermal reduction and even implantation of nitrogen ions. However, quantitative augmentation of favourable oxygen species on the GO films envisaged to act as active sites for the target gas molecules (H2 and SO2 in the current investigation) is yet to be carried out. The present study reports enhancement in detection of gaseous species due to twin mechanisms of a) advantageous tailoring of surface morphology and b) presence of favourable oxygen species. Both the processes are shown to occur due to intentional incorporation of variations induced in the sonication process during synthesis of GO films.