A visible-light activated NO sensor for ppb-level detection based on self-assembled peptide microtubes/SnO/Au hybrids at room temperature.

Gas sensors activated by light and utilizing semiconducting metal oxides (SMOs) are highly promising for next-generation gas detection technologies, owing to advantages such as room-temperature operation, intrinsic safety, and simplified device architecture. Given that noble-metal nanoparticles and eco-friendly organic self-assembled peptide microtubes (SPMTs) can significantly enhance gas-sensing performance, we created a gas sensor activated by visible light, utilizing SPMTs/SnO/Au heterostructures as sensing materials. A systematic investigation was carried out to explore the effects of Au NPs content and light intensity on sensor sensitivity and response. Under visible-light activation, the gas sensor demonstrated outstanding room-temperature sensing performance, achieving a high response value and a low detection limit. The exceptional sensing performance is largely due to the significantly enhanced visible-light absorption and the synergistic interaction among the constituent materials. Under exposure to 4.7 mW/cm visible light irradiation, the sensor exhibited a maximum response of 692.15 to 20 ppm NO. Especially, the response of the sensor to 100 ppb NO attained a value of 5.28, demonstrating its excellent capability to detect low concentrations of NO.