Highly fluorescent carbon dots as selective and sensitive “on-off-on” probes for iron(III) ion and apoferritin detection and imaging in living cells

The One-Step Preparation of Green-Emissioned Carbon Dots through Hydrothermal Route and Its Application

“…However, when the reaction time surpasses 5 h, the color of the product turns dark with an obvious decrease in PL intensity. The optimal reaction time is thus set at 4 h. Under high temperature, DLmalic acid and EDA first undergo dehydration condensation reactions and form polymers, and the polymer then is carbonized into the carbon core [49]. The long reaction time is beneficial to the decomposition of EDA and thus increased the doping ratio of the N element in the carbon core.…”

Shedding light on the effective fluorophore structure of high fluorescence quantum yield carbon nanodots

“…Although different structures, depending on starting materials and reaction conditions, are discussed [3][4][5][6] as the uorescence origin, the immense potential of these so-called carbon dots (CD) has already been successfully proven in several elds such as sensing, optoelectronics, photocatalysis, drug delivery et cetera. [7][8][9][10][11][12] Importantly, the properties of CDs are strongly dependent on their synthesis conditions and reaction precursors. "Bottom-up" fabrication methods from molecular precursors are widely employed, because they allow for high-yield reactions from ecologically friendly starting materials and because the CD products have ultra-high emission quantum yields, low toxicity, and excellent biocompatibility.…”

Highly Luminescent Nitrogen‐Doped Carbon Dots as “Turn‐On” Fluorescence Probe for Selective Detection of Melamine

“…The N 1s XPS spectrum shows three peaks of C−N‐C, C‐N 3 and N−H, which peak at 398.8ex, 399.6ev and 400.6ev, respectively (see Figure D). The O 1s shows two peaks of C=O and C‐OH/C−O‐C, which peak at 530.2ev and 531ev, respectively (see Figure E) ,. The results of XPS spectroscopy are in good agreement with FTIR.…”

“…We analyzed the possible reaction mechanism of fluorescence quenching of N‐CQDs by Fe 3+ from charge/energy transfer effects and chemical structures. The N‐CQDs’ fluorescence was quenched after the addition of Fe 3+ ions, which can be attributed to electron transfer between N‐CQDs and Fe 3+ , which a special coordination interaction between Fe 3+ and N‐CQDs was formed . The FTIR data (see Figure 5D) also proves this.…”

“…The disappear of C−H and N−H bands suggest that ferric ion is connected to the N‐CQDs that form the complex of N‐CQDs‐Fe 3+ . Furthermore, we also explored the Zeta potential of N‐CQDs and N‐CQDs‐Fe 3+ system, the negative zeta potential of N‐CQDs solution has a positive change from −7.9 mv to 13.1mv in the presence of Fe 3+ , which may be attributed to the electron transfer between N‐CQDs and Fe 3+ ,. The N‐CQDs with negative interact with positively charged Fe 3+ ion by electrostatic interaction in water, causing the fluorescence quenching of N‐CQDs.…”