Synthesis of Organophilic Carbon Dots, Selective Screening of Trinitrophenol and a Comprehensive Understanding of Luminescence Quenching Mechanism

Abstract

Abstract Although carbon dots (CDs) are an attractive alternative to the toxic semiconductor based luminescent materials, the plethora of carboxyl group present in its surface bestows a weak solubility in non‐polar media. Here, we demonstrated the synthesis of CDs having high solubility in non‐polar environment referred as ‘organophilic CDs’ (OCDs) via hydrothermal reaction of cyclohexane. Cyclohexane acts as a carbon source as well as dispersion media. The OCDs was well characterized using spectroscopic and microscopic methods. Further, we utilized OCDs for the selective sensing of 2,4,6‐trinitrophenol (TNP) over other structurally similar nitroaromatics (NAs), with a limit of detection of 887 nM. Detailed photophysical studies have been conducted to understand the photoluminescence (PL) quenching mechanism. The quenching was due to primary inner filter effect (IFE), which happens by the absorption of NAs at the excitation wavelength of OCDs and not due to commonly observed electron transfer mechanisms in these class of compounds.