Vafaei, PanizKodu, MargusAlles, HarryKiisk, ValterCasals Guillén, OlgaPrades García, Juan DanielJaaniso, Raivo2025-04-302025-04-302025-01-011424-8220https://hdl.handle.net/2445/220745Low-power gas sensors that can be used in IoT (Internet of Things) systems, consumer devices, and point-of-care devices will enable new applications in environmental monitoring and health protection. We fabricated a monolithic chemiresistive gas sensor by integrating a micro-lightplate with a 2D sensing material composed of single-layer graphene and monolayer-thick TiO2. Applying ultraviolet (380 nm) light with quantum energy above the TiO2 bandgap effectively enhanced the sensor responses. Low (<1 μW optical) power operation of the device was demonstrated by measuring NO2 gas at low concentrations, which is typical in air quality monitoring, with an estimated limit of detection < 0.1 ppb. The gas response amplitudes remained nearly constant over the studied light intensity range (1–150 mW/cm2) owing to the balance between the photoinduced adsorption and desorption processes of the gas molecules. The rates of both processes followed an approximately square-root dependence on light intensity, plausibly because the electron–hole recombination of photoinduced charge carriers is the primary rate-limiting factor. These results pave the way for integrating 2D materials with micro-LED arrays as a feasible path to advanced electronic noses.13 p.application/pdfengcc-by (c) Vafaei, P. et al., 2025http://creativecommons.org/licenses/by/4.0/GrafèDetectors de gasosDiòxid de titaniGrapheneGas detectorsTitanium dioxideinfo:eu-repo/semantics/article7566982025-04-30info:eu-repo/semantics/openAccess