White‐Light‐Emitting Carbon Dots Prepared by the Electrochemical Exfoliation of Graphite

Abstract

The single-step synthesis of white-light-emitting carbon dots (CDs) through a green, facile and cheap electrochemical route by using graphite rods as the carbon source is reported. Under UV excitation, the aqueous dispersion of as-synthesised CDs exhibit broad-band emission, which covers a significant fraction of the visible spectrum, owing to the heterogeneity in particle size and surface functional groups. The CDs were further explored for their potential as UV-to-visible colour convertors under remote-phosphor technology by capping a λ=365 nm UV light-emitting diode (LED) chip with CD-loaded poly(methyl methacrylate) to obtain the following colour parameters: Commission Internationale de l'Eclairage chromaticity coordinates (0.35, 0.37), colour rendering index (88) and correlated colour temperature (4802 K).

Green synthesis, biomedical and biotechnological applications of carbon and graphene quantum dots. A review

“…Various chemical precursors have been detected for generating carbon dots, including ammonium citrate , ethylene glycol (Jaiswal et al 2012), citric acid (Schneider et al 2017), ethylene diamine tetra acetic acid (EDTA) (Liu et al 2017a), phytic acid (Wang et al 2013d), phenylenediamine (Vedamalai et al 2014), thiourea (Wang et al 2016a), carbon nanotube (Shinde and Pillai 2012) and graphite (Joseph and Anappara 2017). Meanwhile, diverse green carbon precursors have been applied for the production of carbon dots including fruits, their juices and fruit peels (Mehta et al 2015), animal and animal-derived materials such as chicken egg (Zhang et al 2015c) and silkworm , vegetables and spices , waste kitchen materials like frying oil (Xu et al 2015) or waste paper (Wei et al 2014), plant leaves and derivatives ), among others.…”

Boron Doped Carbon Dots with Unusually High Photoluminescence Quantum Yield for Ratiometric Intracellular pH Sensing

“…Recent surge in research indicates that bio-friendly carbon dots with the ability to synthesize easily and functionalization, [1] optical properties, [2] and potential applications in diverse fields such as in catalysis, [3] drug delivery, [4] sensing, [5][6][7][8][9] bioimaging, [10] energy storage [11] and conversion, [12] and in light emitting devices [13][14][15] are viable alternatives to semiconductor quantum dots and the metal based nanoparticles. Notably, the optical and possibly other properties of the carbon dots could be tuned by doping with hetero atoms such as the nitrogen (N) sulfur (S) phosphorous (P) and boron (B).…”

Synthesis of Longer‐Wavelength‐Emissive Carbon Quantum Dots for WLEDs and Investigation of Their Photoluminescence Properties

“…As a new class of fluorescent nanomaterial's, carbon quantum dots (CQDs) have attracted emergent interest in last decade and are used in diverse applications such as biomedicine, cell‐imaging, optoelectronic devices, sensors, and catalysis . Recently, fluorescent CQDs have been applied as a new class of phosphors for the development of WLEDs, because of their unique properties including tunable fluorescence emission, and high thermal with photo stability, easy preparation, low cost, environment friendliness and easy surface functionalization .…”

“…As a new class of fluorescent nanomaterial's, carbon quantum dots (CQDs) have attracted emergent interest in last decade and are used in diverse applications such as biomedicine, cell-imaging, optoelectronic devices, sensors, and catalysis. [9][10][11][12][13] Recently, fluorescent CQDs have been applied as a new class of phosphors for the development of WLEDs, because of their unique properties including tunable fluorescence emission, and high thermal with photo stability, easy preparation, low cost, environment friendliness and easy surface functionalization. [14][15][16][17][18] Although the above properties are needed to achieve CQDs as a good phosphor, but simultaneously CQDs earned two important properties i. e. one is strong emission at longer wavelength region and other one is high quantum yield.…”