Effect of the\nChemical Structure of a Self-Assembled\nMonolayer on the Gas-Sensing Behavior of SnO<sub>2</sub> Nanowires

In this study, detailed investigations of the selective\nsensing\ncapability of semiconducting metal oxide (SMO)-based gas sensors with\nself-assembled monolayer (SAM) functionalization were conducted. The\nselective gas-sensing behavior was improved by employing a simple\nand straightforward postmodification technique using functional SAM\nmolecules. The chemical structure of the SAM molecules promoted interaction\nbetween the gas and SAM molecules, providing a gas selective sensing\nof SnO<sub>2</sub> nanowires (NWs). In addition, a bundle of SnO<sub>2</sub> NWs provided a large surface area that could act as a sensing\nsite. SAM functionalization was confirmed by infrared spectroscopy\nand thermogravimetric analysis, and the selective gas-sensing behaviors\nwere investigated under different sensing conditions. With variations\nin the chemical structures of the SAM molecules, the selective gas-sensing\nbehaviors also changed as the corresponding intermolecular interaction\nforces were different. This integration of selective gas sensing and\npassivation of a sensing surface provides a straightforward approach\nfor the preferred gas sensing of SnO<sub>2</sub> NWs. Furthermore,\nowing to the universal binding characteristics of SAM molecules to\nthe metal oxide surface, this approach can be expanded to other SMO-based\ngas-sensing platforms.