Reduced graphene oxide/ZnO nanocomposites: one-step solid-state preparation for room temperature photo-sensing and photoelectrical gas sensing capabilities†

Detecting triethylamine (TEA), which is a highly active industrial chemical, is crucial in today's globalized world with increasing air pollution. In this work, we propose reduced graphene oxide (rGO)/ZnO nanocomposites for efficient TEA detection under ultraviolet (UV) light activation at room temperature. rGO@ZnO nanocomposites with different rGO weight percentages (1, 2.5, 5, and 10 wt%) were synthesized through a scalable, one-step solid-state method and characterized using various physicochemical techniques. Among the samples, the 2.5wt% rGO@ZnO nanocomposite (2.5%G@ZnO) exhibited the highest photo-response after UV light irradiation, indicating its superior carrier concentration generation under UV light. TEA sensing studies were carried out under UV light using sensors based on pristine ZnO nanopowder and the 2.5%G@ZnO nanocomposite. The 2.5%G@ZnO sensor demonstrated a significantly enhanced TEA sensing response (35%) compared with pristine ZnO, and it exhibited a lower detection limit of 15.6 ppm at room temperature. The sensing mechanism was explained using the depletion layer model, accompanied by scanning Kelvin probe analysis, which highlighted the role of UV light activation in improving sensor performance. These findings underscore the potential of UV-activated rGO/ZnO nanocomposite sensors for sensitive and efficient TEA detection.