Green synthesis of carbon dots with down- and up-conversion fluorescent properties for sensitive detection of hypochlorite with a dual-readout assay

Abstract

High quality carbon dots (C-dots) with down- and up-conversion fluorescence have been synthesized through low-temperature carbonization using sweet pepper as the carbon source. The C-dots with a quantum yield (QY) of 19.3% exhibit superior photophysical properties, for example, narrow and symmetric emission spectra, large stock shifts, resistance to photobleaching, and excitation-dependent fluorescence behavior. The excellent C-dots serve as useful fluorescent probes for hypochlorite (ClO(-)) detection by both down- and up-conversion fluorescence. Two consecutive linear ranges allow a wide determination of ClO(-) concentrations with a low detection limit of 0.05 μmol L(-1) and 0.06 μmol L(-1) (S/N = 3) for down- and up-conversion fluorescence measurements, respectively. The proposed detection method is advantageous because it is simple, sensitive, dual-signalling model and low-cost and has potential extensive applications in environmental and biological assays.

One-step Synthesis of Highly Luminescent Nitrogen-doped Carbon Dots for Selective and Sensitive Detection of Mercury(II) Ions and Cellular Imaging

“…S4B, Supporting Information) was measured to be -24.7 mV, originating from the existence of hydroxyl and carboxylic/carbonyl moieties on the surface of N-CDs. 42 The stability of the N-CDs. The stability of N-CDs in a solution of 10 mM PBS (pH 7.4) was investigated under different concentrations of sodium chloride (NaCl).…”

Biogenic Synthesis of Fluorescent Carbon Dots at Ambient Temperature Using Azadirachta indica (Neem) gum

“…Only decrease in intensity of peak was observed after CDs were excited at 420 nm which may be due to insignificant absorption of CDs in visible range. This excitation dependent emission spectra is a signature [24]. The fluorescence property of CDs is considered to be the result of surface energy traps and quantum confinement [10].Upon exposure to UV light (λ = 388 nm) CDs solution showed green turbid fluorescence (Inset b of Fig.…”

Carbon dots: synthetic methods and applications as fluorescent probes for the detection of metal ions, inorganic anions and organic molecules

“…There was a good linear relationship toward the concentration of HClO in the range of 0.2-2 μM; the detection limit was 15 nM. Yin's group set up a green synthetic method for down-and up-conversion fluorescent CDs [83]. The CDs could be used to detect HClO through the same process.…”