Room Temperature N2O Detection by UV-Assisted SnO2-TiO2 Sensor Elements Fabricated by Atmospheric PLD

In this work, we report the fabrication of SnO2-based composite nanostructures in view of their application as a sensor element toward N2O gas exposure. The samples were produced by laser ablation of a composite SnO2-TiO2 target performed in air at atmospheric pressure (in open air). We examined how the structure, morphology, composition, and physical properties of the samples change with the TiO2 content being introduced into the SnO2 target. The laser ablation of SnO2-based targets in open air produced samples with a structure in which SnO2 and SnO crystal phases co-existed, as the crystal phases were distinguished in separate nanoparticles. The nanoparticles formed a complex porous structure with oxygen-related defects. We investigated the gas-sensing properties of composite SnO2-based sensor elements working under UV irradiation. The highest response to N2O exposure and the fastest response/recovery times were demonstrated by the sensor element produced by the laser ablation of a composite target prepared by 10 wt% TiO2 in SnO2. Additionally, we found that a small amount (below 0.1 wt%) of noble metal (Pt) added to the sensor element substantially improved the gas sensor performance without inducing significant structural and/or morphological changes. Further, we explored how simultaneous irradiation of the sensor surface with UV and visible light changes the sensor properties. The best sensor performance toward N2O exposure was achieved by irradiating the Pt-doped SnO2-TiO2 sensor surface simultaneously with UV and red lights.