Practical access to bandgap-like N-doped carbon dots with dual emission unzipped from PAN@PMMA core–shell nanoparticles

Abstract

As emergent nanolights for bioimaging, catalysis, sensors, and photoelectronics, carbon dots (C-dots) have attracted much research attention. However, the practical and scalable preparation of C-dots has been less explored, even after various top-down and bottom-up approaches being reported recently. To this end, we discover a new approach to prepare C-dots by simply unzipping core-shell polymeric nanoparticles, prepared by a microemulsion polymerization. Uniformly distributed N-doped C-dots are prepared by the pyrolysis of PAN@PMMA core-shell nanoparticles at different temperatures, followed by dialysis. TEM analysis shows that many of the C-dots of 2-3 nm size are unzipped from each polymeric particle. All the purified C-dots show a bandgap-like photoluminescence (PL) behaviour, with dual emission and a stable PL between pH 5-12.

Naked oats-derived dual-emission carbon nanodots for ratiometric sensing and cellular imaging

“…4b). Interestingly, dual emission bands, UV band and blue band, are observed in the excitation wavelength range which can be attributed to the emission from the core and the surface states [33,35,37], respectively. It should be noted that with increasing excitation wavelength PL intensity changes obviously.…”

“…Xiong et al [36] reported novel long-chain cationic surfactant (nonylphenol polyethylene glycol quaternary ammonium salt (NPEQ)) coated CDs through ionic interaction and discovered that the aqueous solution of obtained CDs presented distinct dual emission peaks ascribing to a partial ionization of NPEQ molecules from CDs. Hu et al [37] applied an effective approach to prepare dual emission N-doped CDs by the pyrolysis of PAN (Poly Acrylonitrile)@PMMA (Poly Methyl methacrylate) core-shell nanoparticles at different temperatures and clarified the PL mechanism of the CDs originating from the amide groups (or imine groups) of the surface and the amorphous carbonaceous core. Nevertheless, all these methods suffer from some drawbacks like the requirement of tedious synthetic methodology or the use of toxic/expensive solvents and starting materials.…”

Characterization of single-chain polymer folding using size exclusion chromatography with multiple modes of detection

“…A fast growing research area, single-chain nanoparticles (SCNP) have demonstrated promise for use in catalysis [1], nanoreactors [2], controlled release [3], chemical sensors [4], enzyme mimetics [5][6][7], diagnostics [8] and optics [9]. This breadth of application is attributed to the precise control over the composition, functionality, geometry and topology this technology permits for accessing architectures in the sub-20 nm size regime.…”

Highly fluorescent C-dots obtained by pyrolysis of quaternary ammonium ions trapped in all-silica ITQ-29 zeolite

“…8 Fluorescent C-dots could be a viable alternative to conventional quantum dots based on sulphides or chalcogenides of transition metals that in the most widely employed cases such CdSe, CdTe and PbS are highly toxic. [9][10][11][12][13][14][15] Two general methodologies, either top down 11,16 or bottom up 17,18 have been applied for the synthesis of C-dots. Among these reported synthetic methodologies for the preparation of fluorescent C-dots those that have attracted more attention due to their simplicity have been hydrothermal carbonisation under various conditions of suitable molecular or polymeric precursors, [19][20][21] but also laser ablation 16,22 and arc discharge 23 have been widely employed.…”