Flexible hydrogen gas sensor based on a capacitor-like Pt/TiO2/Pt structure on polyimide foil

• Published in: International journal of hydrogen energy 2021-05, Vol.46 (36), p.19217-19228
• Main Authors: Vidiš, Marek, Shpetnyi, Ihor O., Roch, Tomáš, Satrapinskyy, Leonid, Patrnčiak, Michal, Plecenik, Andrej, Plecenik, Tomáš
• Format: Article
• Language: English
• Subjects: Capacitor-like; Flexible; Gas sensor; TiO2
• ISSN: 0360-3199; 1879-3487
• DOI: 10.1016/j.ijhydene.2021.03.052

Metal oxide semiconductor gas sensors of hydrogen with a typical capacitor-like Pt/TiO2/Pt electrode arrangement exhibit excellent sensitivity to hydrogen even at room temperature. At the same time, very similar Pt/TiO2/Pt cells can also be used as memristive elements exhibiting resistive switching between two resistive states, which has been recently exploited to create a gas sensor with built-in memory. Merging of these two functionalities within a single device also opens new possibilities for smart gas sensor arrays. However, so far such sensors have been prepared only on rigid substrates. In this work, a flexible hydrogen gas sensor with such capacitor-like Pt/TiO2/Pt electrode arrangement fabricated on polyimide foil is presented and characterized in terms of hydrogen gas sensing properties and bending endurance. The sensor exhibits high response (Rair/RH2) of more than 105 to 10 000 ppm H2 at 150 °C with minor decline at elevated humidity and is capable of room temperature operation. The lowest detected concentration was 3 ppm at 150 °C and 300 ppm at room temperature in dry conditions. Bending the sensor 105 times over diameter of 10 mm led to slight improvement of the sensing performance. •Flexible TiO2 thin film based H2 sensor has been fabricated on polyimide foil.•A capacitor-like Pt/TiO2/Pt electrode arrangement, similar to a memristor cell.•Room temperature operation in dry environment as well as at elevated humidity.•Slightly better performance after bending the sensor 105 times over 1 cm diameter.