One pot selective synthesis of water and organic soluble carbon dots with green fluorescence emission

Abstract

This work reports a simple and energy-saving strategy for selective synthesis of water-soluble and organic-soluble carbon dots at room temperature.

Oil-Dispersible Green-Emitting Carbon Dots: New Insights on a Facile and Efficient Synthesis

“…In particular, deconvolutions of the PL spectra ( Figure S2) demonstrate that the overall area associated with the emission of the residual blue-emitting intermediates in purified O-CDs is less than the 10% of the overall area of the PL spectrum, at all the investigated λ exc values. The absolute QY of the purified O-CDs measured at 410 nm is 16 ± 1%, in agreement with the work of Zheng et al [24], while the value for the W-CDs is limited to a few percent. The spectral deconvolution of the PL band for O-CDs is also used to assess a reliable value of the QY of the green emission of the O-CDs only, estimating the contribution of the emission of the blue fluorophores that results in the experimental error on the measure.…”

“…Interestingly, the O-CDs have been shown to be, to some extent, dispersible in all the tested solvents. Such behavior is compatible with the characteristic heterogeneity in the surface composition of the CDs, where both polar and apolar groups (e.g., -COOH, -C=O, -OH, -C=N or CPC residual alkyl chains [24,25]) make the O-CDs dispersible in a variety of solvents with different polarities. Figure 2 shows a comparison between the PL spectra of a purified O-CD sample, re-dispersed in CHCl 3 , and the spectrum of the relative supernatant (non-solvent based) obtained after centrifugation, recorded at different λ exc .…”

“…However, the possibility of safely inferring the exact origin of the electronic transitions giving rise to these bands is not trivial: similar absorption bands above 300 nm are often related to the n-π * transitions of the surface-related chemical groups of the CDs that form a system of multiple discrete energy states [29,43,44,[47][48][49]. However, other reports [24,25,50,51] ascribe them to the π-π* and n-π* transitions, respectively, of the characteristic interconnected heteroaromatic units of the CDs. It is also worth noting that all the absorption spectra show a characteristic scattering background that decreases monotonically at increased wavelengths.…”

Sunlight-induced photoreduction of Cr(VI) to Cr(III) in wastewater by nitrogen-phosphorus-doped carbon dots

“…2e). 33 FTIR results (Fig. 2f) show a broad band from 3484 to 3200 cm −1 corresponding to the N-H (sharp end) and O-H stretching vibrations.…”

A switchable peroxidase mimic derived from the reversible co-assembly of cytochrome c and carbon dots

“…In addition to these surface features which impart C-dots with high aqueous solubility, C-dots also sport several other attractive and exploitable properties (especially in relation to bio-applications), such as biocompatibility, low cytotoxicity, excitation wavelength-dependent emission, and relatively high luminescence quantum yields. 10,11 One other appealing feature of C-dots is the ability to generate this nanomaterial from virtually any carbon-containing source, including low-and negatively-valued wastes (even human urine 12 ) through an arsenal of top-down (e.g., arc discharge, laser ablation, electrochemical oxidation) and bottom-up (e.g., thermal, hydrothermal, and microwave) approaches. 10 While C-dots appear to be interesting candidates for efficient enzymatic modulation, past protein-related C-dot work has focused primarily on protein detection [13][14][15] or insulin fibrillation inhibition, 16 with few reports relevant to C-dot modulated enzyme activity, the nature of protein/C-dot interactions, or the effects of C-dots on protein structure.…”