Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection
Low-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 sen...
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MDPI AG
2025-01-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/25/2/382 |
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| author | Paniz Vafaei Margus Kodu Harry Alles Valter Kiisk Olga Casals Joan Daniel Prades Raivo Jaaniso |
| author_facet | Paniz Vafaei Margus Kodu Harry Alles Valter Kiisk Olga Casals Joan Daniel Prades Raivo Jaaniso |
| author_sort | Paniz Vafaei |
| collection | DOAJ |
| description | Low-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 TiO<sub>2</sub>. Applying ultraviolet (380 nm) light with quantum energy above the TiO<sub>2</sub> bandgap effectively enhanced the sensor responses. Low (<1 μW optical) power operation of the device was demonstrated by measuring NO<sub>2</sub> 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/cm<sup>2</sup>) 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. |
| format | Article |
| id | doaj-art-b9b1f670052c4222b50de152239ea495 |
| institution | Kabale University |
| issn | 1424-8220 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj-art-b9b1f670052c4222b50de152239ea4952025-01-24T13:48:42ZengMDPI AGSensors1424-82202025-01-0125238210.3390/s25020382Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas DetectionPaniz Vafaei0Margus Kodu1Harry Alles2Valter Kiisk3Olga Casals4Joan Daniel Prades5Raivo Jaaniso6Institute of Physics, University of Tartu, EE-50411 Tartu, EstoniaInstitute of Physics, University of Tartu, EE-50411 Tartu, EstoniaInstitute of Physics, University of Tartu, EE-50411 Tartu, EstoniaInstitute of Physics, University of Tartu, EE-50411 Tartu, EstoniaMIND-IN2 UB, Department of Electronics and Biomedical Engineering, Universitat de Barcelona, E-08028 Barcelona, SpainLaboratory for Emerging Nanometrology (LENA), Institute of Semiconductor Technology (IHT), Technische Universität Braunschweig, Hans-Sommer Str. 66, 38106 Braunschweig, GermanyInstitute of Physics, University of Tartu, EE-50411 Tartu, EstoniaLow-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 TiO<sub>2</sub>. Applying ultraviolet (380 nm) light with quantum energy above the TiO<sub>2</sub> bandgap effectively enhanced the sensor responses. Low (<1 μW optical) power operation of the device was demonstrated by measuring NO<sub>2</sub> 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/cm<sup>2</sup>) 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.https://www.mdpi.com/1424-8220/25/2/382gas sensorNO<sub>2</sub>micro-lightplategrapheneTiO<sub>2</sub> |
| spellingShingle | Paniz Vafaei Margus Kodu Harry Alles Valter Kiisk Olga Casals Joan Daniel Prades Raivo Jaaniso Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection Sensors gas sensor NO<sub>2</sub> micro-lightplate graphene TiO<sub>2</sub> |
| title | Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection |
| title_full | Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection |
| title_fullStr | Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection |
| title_full_unstemmed | Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection |
| title_short | Graphene/TiO<sub>2</sub> Heterostructure Integrated with a Micro-Lightplate for Low-Power NO<sub>2</sub> Gas Detection |
| title_sort | graphene tio sub 2 sub heterostructure integrated with a micro lightplate for low power no sub 2 sub gas detection |
| topic | gas sensor NO<sub>2</sub> micro-lightplate graphene TiO<sub>2</sub> |
| url | https://www.mdpi.com/1424-8220/25/2/382 |
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