Ammonia Vapour Detection at Room Temperature via Carbon Quantum Dots based Facile System

With widespread industrial use of ammonia and its potential hazards to both human health and the environment, ensuring reliable detection has become paramount. In the present work, we report a study on a novel and highly sensitive gas sensing material, composed of carbon quantum dots (CQDs) for the detection of ammonia vapor at room temperature. The CQDs were synthesized at 200 °C using a hydrothermal single-step process. To investigate the morphology and chemical composition, CQDs were characterized by Fourier transform infrared spectroscopy, Transmission Electron Microscopy, photoluminescence, and UV-Vis spectroscopy. A thin-film of CQDs was then deposited on an ITO-coated glass substrate for the detection and quantification of ammonia vapor (NH3) by monitoring the response under ambient conditions. By corresponding change in conductance, the change in resistance of the film is investigated. The enhanced properties of sensing of the ammonia samples may be due to the combined effect of localized electronic surface states of CQDs and chemical sensitization caused by the catalytic properties of an active functional group on the CQDs surface. Notably, this sensor exhibits higher sensitivity, excellent response time, and greater stability to ammonia vapours compared to previous reports.