Carbon Nanoparticles as Chromophores for Photon Harvesting and Photoconversion

Abstract

Carbon nanomaterials have generated a tremendous amount of attention in the scientific community. While most of the research and development efforts have been on fullerenes, carbon nanotubes, and graphene sheets, carbon nanoparticles (which are often considered as impurities or unwanted complications in the other carbon nanomaterials) have recently emerged as a unique class of highly fluorescent nano-dots. However, little or no attention has been paid to potential uses of carbon nanoparticles as chromophores in photochemical reactions or for photon harvesting and photoconversion in general. In the study reported herein we demonstrate the chromophore-equivalent functions of aqueous-suspended small carbon nanoparticles in harvesting visible photons for the reductive coating of the nanoparticles with silver and gold and, as a result, the preparation of unique carbon-noble-metal core-shell nanostructures.

Carbon Quantum Dots and Applications in Photocatalytic Energy Conversion

“…[16][17][18][19] As in the original study, 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 6 carbon nanoparticles of 5-10 nm in diameter suggested absorptivity values of 50-100 M C-atom -1 cm -1 around 450 nm, where M C-atom denotes molar concentration in terms of carbon atoms in the core carbon nanoparticles, compared with 16 M C-atom -1 cm -1 for C 60 at the first absorption band maximum. 28 These absorptivity values are roughly the equivalent of up to 750,000 and 6 × 10 6 M C-particle -1 cm -1 for the carbon nanoparticles of 5 and 10 nm in diameter, respectively. Carbon dots with effective surface passivation are brightly fluorescent.…”

“…28 The suspended carbon nanoparticles could also harvest visible photons for the photo-reductive deposition of a noble metal like gold or platinum to yield metal-doped carbon nanoparticles. 28 The carbon nanoparticles without metal doping were found to be generally poor in photocatalytic performance in the CO 2 reduction, while those with gold doping exhibited significant improvements, though still not competitive to their surface-passivated counterparts. 70 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 29…”

Quercetin-mediated synthesis of graphene oxide–silver nanoparticle nanocomposites: a suitable alternative nanotherapy for neuroblastoma

“…For example, attachment of AgNPs on the surface of GO sheets can prevent AgNPs from aggregating, allowing a more controlled release of AgNPs + ions, which eventually can increase antibacterial and anticancer activity. 21,37,[39][40][41][42] Recent studies on basic and translational cancer have been focused on development of novel therapeutic agents targeting multidimensional aspects that contribute to the development and progression of cancers and the resistance of tumors to conventional therapies. 43,44 Although several studies have addressed the molecular mechanism of cancer pathogenesis, the process of understanding remains extremely complex, and much is still unknown because of intrinsic resistance and loss of sensitivity to a therapeutic agent.…”

Strongly tricolor-emitting carbon dots synthesized by a combined aging–annealing route and their bio-application

“…As a new class of viable uorescent nanomaterials, CDs have shown tremendous potentials as versatile nanomaterials for a wide range of applications, including chemical sensing, bio-sensing, 3,4 bio-imaging, 5,6 photocatalysis, 7 drug delivery 8 and electrocatalysis, 9 because of their stable photoluminescence, low cytotoxicity, excellent biocompatibility, and environmental compatibility. Generally, synthetic approaches for CDs are classied into two categories "topdown" 10,11 and "bottom-up". [12][13][14][15][16] The former involves breaking down larger carbon structures, such as nanodiamonds, graphite, carbon nanotubes, carbon soot, activated carbon and graphite oxide by methods like arc discharge, 10 laser ablation, and electrochemical oxidation.…”

“…Generally, synthetic approaches for CDs are classied into two categories "topdown" 10,11 and "bottom-up". [12][13][14][15][16] The former involves breaking down larger carbon structures, such as nanodiamonds, graphite, carbon nanotubes, carbon soot, activated carbon and graphite oxide by methods like arc discharge, 10 laser ablation, and electrochemical oxidation. 12 On the other hand, the "bottom-up" approaches synthesize CDs from molecular precursors such as ascorbic acid, 13 glucose 14 and polymer-silica nanocomposites 15 through combustion, hydrothermal treatments/aging, calcination/annealing, and microwave synthetic routes.…”