Dual Improvement in Sensitivity and Humidity Tolerance of a NO2 Sensor Based on 3-Aminopropyltriethoxysilane Self-Assembled Monolayer-Functionalized SnSe2 for Explosive Photolysis Gas Detection

Explosives can be analyzed for theircontent by detecting the photolyticgaseous byproducts. However, to prevent electrostatic sparking, explosivesare frequently preserved in conditions with low temperatures and highhumidity, impeding the performance of gas detection. Thus, it hasbecome a research priority to develop gas sensors that operate atambient temperature and high humidity levels in the realm of explosivebreakdown gas-phase detection. In this work, 3-aminopropyltriethoxysilane(APTES) self-assembled monolayer-functionalized tin diselenide (APTES-SnSe2) nanosheets were synthesized via a facilesolution stirring strategy, resulting in a room-temperature NO2 sensor with improved sensitivity and humidity tolerance.The APTES-SnSe2 sensor with moderate functionalizationtime outperforms the pure SnSe2 sensor in terms of theresponse value (317.51 vs 110.98%) and response deviation(3.11 vs 24.13%) under humidity interference to 500ppb NO2. According to density functional theory simulations,the stronger adsorption of terminal amino groups of the APTES moleculesto NO2 molecules and stable adsorption energy in the presenceof H2O are the causes of the improved sensing capabilities.Practically, the APTES-SnSe2 sensor achieves accurate detectionof photolysis gases from trace nitro explosives octogen, pentaerythritoltetranitrate, and trinitrotoluene at room temperature and varioushumidity levels. This study provides a potential strategy for theconstruction of gas sensors with high responsiveness and antihumiditycapabilities to identify explosive content in harsh environments.