Optimization of multilayer graphene-based gas sensors by ultraviolet photoactivation

• Published in: Applied surface science 2023-02, Vol.610, p.155393, Article 155393
• Main Authors: Peña, Álvaro, Matatagui, Daniel, Ricciardella, Filiberto, Sacco, Leandro, Vollebregt, Sten, Otero, Daniel, López-Sánchez, Jesús, Marín, Pilar, Horrillo, Mari Carmen
• Format: Article
• Language: English
• Subjects: Ammonia; Carbon monoxide; Graphene gas sensors; Limit of detection; Nitrogen dioxide; Ultraviolet
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2022.155393

[Display omitted] •The density of defects on CVD graphene affects its sensing performance.•Ultraviolet irradiation promotes full recovery and improved reproducibility.•Ultraviolet irradiation allows extremely low limits of nitrogen dioxide detection.•Tuning ultraviolet irradiation parameters change the sensing dynamics.•Ultraviolet irradiation effect was confirmed for nitrogen dioxide, ammonia and carbon monoxide. Nitrogen dioxide (NO2) is a potential hazard to human health at low concentrations, below one part per million (ppm). NO2 can be monitored using gas sensors based on multi-layered graphene operating at ambient temperature. However, reliable detection of concentrations on the order of parts per million and lower is hindered by partial recovery and lack of reproducibility of the sensors after exposure. We show how to overcome these longstanding problems using ultraviolet (UV) light. When exposed to NO2, the sensor response is enhanced by 290 % − 550 % under a 275 nm wavelength light emitting diode irradiation. Furthermore, the sensor's initial state is completely restored after exposure to the target gas. UV irradiation at 68 W/m2 reduces the NO2 detection limit to 30 parts per billion (ppb) at room temperature. We investigated sensor performance optimization for UV irradiation with different power densities and target gases, such as carbon oxide and ammonia. Improved sensitivity, recovery, and reproducibility of UV-assisted graphene-based gas sensors make them suitable for widespread environmental applications.