Influence of heteroatom doping in tuning fluorescence of carbon dots for detection of pendimethalin and indoxacarb with different mechanisms

초록

In this study, Sapindus mukorossi (soapnut, abbreviated as "SN") fruits were used as a green precursor to synthesize carbon dots (CDs) through hydrothermal (named as SNCDs-HT) and acid carbonization (named as SNCDs-AC) methods, with a focus on comparing their optical properties and fluorescence response to pesticide detection. SNCDs-HT exhibited blue fluorescence with emission/excitation wavelengths (lambda Em/Ex) at 418/334 nm, while SNCDs-AC displayed green fluorescence with lambda Em/Ex at 525/424 nm. Various characterization techniques were employed to analyze the optical properties and surface functionalities of both CDs. The emission intensity of SNCDs-HT decreased proportionally with increasing concentrations of pendimethalin (PNM) ranging from 1 to 140 mu M. In contrast, SNCDs-AC responded to indoxacarb (INC) concentrations in the range of 0.05 to 100 mu M through a fluorescence quenching mechanism. The incorporation of heteroatoms (phosphorus) in SNCDs-AC not only altered their optical properties but also enhanced their sensing capabilities compared to SNCDs-HT. Notably, the quantum yield (QY) of SNCDs-HT was calculated to be 12.2%, whereas SNCDs-AC demonstrated a higher QY of 21.7%, underscoring the effectiveness of heteroatom doping in improving fluorescence efficiency. This study presents a novel approach to tailor the optical properties and sensing performance of CDs through heteroatom doping, offering significant potential for environmental monitoring applications.

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