Luminescent S-doped carbon dots: an emergent architecture for multimodal applications

Abstract

A facile route has been developed to synthesise and isolate sulphur doped fluorescent carbon dots for the first time. Such carbogenic quantum dots exhibit a wide band gap of 4.43 eV with a high open circuit voltage (V OC ) of 617 mV along with a fill factor (FF) as high as 37%, using phenyl-C60-butyric acid methyl ester (PCBM) as the electron transporting layer. Besides the wide band gap, which is useful in the fabrication of solar cells, sulphur modified carbon dots also exhibit a high fluorescence quantum yield of 11.8% without any additional surface passivation, producing a unique fluorescent probe for further applications. In addition, the particles have a strong tendency to interact with the surface of gold nanoparticles and produce a thin fluorescent layer over their surfaces. Moreover, as they are completely biocompatible in nature, the highly fluorescent S-doped carbon dots have a strong potential for use in bioimaging applications. Interestingly, owing to the presence of oxygen and sulphur functionality, the highly negatively charged particles can easily bind with positively charged DNA-PEI complexes, simply by mixing them, and after interaction with DNA, bright blue fluorescence has been observed under an excitation wavelength of 405 nm .

One-step synthesis of silver nanoparticles using carbon dots as reducing and stabilizing agents and their antibacterial mechanisms

“…All of the spectrum can be fitted into four types of carbon bond, corresponding to sp 2 (C=C) at 284.5-284.6, sp 3 (C-C) at 14 285.4-285.6, C-OH at 286.3-286.7, as well as C=O at 287.4-287.9 eV [28]. However, C-S may also exist in AgNPs3 and AgNPs4 for both the binding energy of C-S, C-C are near 285.5 eV [39,40].It should be noted that XPS only reflects the surface components of AgNPs, the relative contents of the core component cannot be obtained.…”

Carbon dots-based fluorescent probe for “off-on” sensing of Hg(II) and I

“…2010;Hu et al, 2013;Li et al, 2013;Bourlinos et al, 2008). As a result, it makes them promising candidates for numerous exciting applications, such as bioimaging Wang et al, 2011), photocatalysis , LED (Guo et al, 2012;Wang et al, 2010), energy conversion (Chandra et al, 2013), photovoltaic devices (Gupta et al, 2011;Feng et al, 2009;Yan et al,2010), medical diagnosis (Kong et al,2012) and sensing (Zhu et al, 2013;Qu et al, 2013). Now, many approaches for the synthesis of CDs have been reported, such as combustion, ultrasonic treatment, arc discharge, electrochemical oxidation, laser ablation, thermal treatment, acid reflux and microwave methods.…”

Nitrogen and sulfur co-doped carbon dots for highly selective and sensitive detection of Hg (Ⅱ) ions

“…For example, C-dots doped with ZnS and functionalized with oligomeric poly(ethylenelycol) diamine (PEG 1500N) have shown very high FLQY up to 78% (Anilkumar et al, 2011). Heteroatom (e.g., N, B, S, and Si) doping with or without surface modifications (Qian et al, 2014;Chandra et al, 2013;Hu, Y., et al, 2014), especially N-doping or co-doping with N and another element, has also been actively investigated to improve the FLQY of C-dots Zhang, Y.Q., et al 2012;Gao et al, 2014;Yang et al, 2014;Wei et al, 2014;Qu et al, 2014). By using citric acid and urea as C and N sources, respectively, Qu et al (2012) reported a one-step microwave synthesis of N-doped C-dots (N/C-dots) with FLQY of about 14%.…”