Carbon dots/silicone rubber composites for fluorescence detection of biodiesel in fuel blends

Abstract

Carbon-based nanoparticles, specifically carbon quantum dots (CQDs), have received growing interest significantly owing to their optical characteristics and production simplicity. Their diverse surface functionality and media solubility have been used to demonstrate their electronic, biological, and chemical applications. CQDs polymer composites have been widely exhibited in the case of functional applications in related areas by using CQDs' unique properties. On the detection applications of biofuels, numerous spectroscopic and instrumental approaches have been developed in the literature. Here, organic soluble r-CQDs (QY: 72%) have been synthesized to fabricate fluorescent cross-linked silicone composites that are capable of sensing the biodiesel amount in fuel mixtures by solvatochromic shifts. The fluorescent rubber composites were tested with various degrees of biodiesel blends in 24 h for maximal swelling, and approximately 70% absorption was achieved. The capacity to distinguish biodiesel levels has been effectively revealed with an error level of 2.9 nm at the photoluminescence spectral peak, whereas biodiesel levels were as low as 10%. The colorimetric shift of the swollen composites were also sufficient to identify the biodiesel content visually under UV lights.