Blue Luminescent Graphene Quantum Dots by Photochemical Stitching of Small Aromatic Molecules: Fluorescent Nanoprobes in Cellular Imaging

Abstract

Blue fluorescent graphene quantum dots (GQDs) are synthesized from small haloaromatic molecules by laser photochemistry. The process involves a bottom‐up photochemical stitching mechanism of the free radicals generated by irradiation of ultraviolet photons (λ = 248 nm) on o‐dichlorobenzene. The GQDs are further demonstrated to be of importance as fluorescent nanoprobes in bioimaging of cells.

Recent Advances in Graphene Quantum Dots as Bioimaging Probes

“…Moreover, due to their similarity in structure, polycyclic aromatic hydrocarbons are generally regarded as nanoscaled fragments of graphene, which gives them great promise for preparing monodispersed GQDs with precisely tailored structure, morphology and size. Aromatic molecules, such as diphenylacetylene [39], hexa-peri-hexabenzocoronene [29], pyrene [123,124], benzo[a]pyrene or naphtho [2,pyrene [123], 4-bromo-3-iodobenzoic acid [125][126][127] and o-dichlorobenzene (DCB) [128], are employed as precursors through successive carbonization, oxidization, surface functionalization and reduction process, or utilizing stepwise solution chemistry strategies to prepare GQDs successfully. Furthermore, doping and/or surface passivation are effective methods to modulate the electronic density of bulk semiconductor materials and to tune their optical and electrical properties.…”

“…Also, nitrogen and sulfur co-functionalized GQDs are successfully obtained using nitrogen and sulfur containing compounds of 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl) imide [68], polythiophene [136] and thiourea [110]. Moreover, o-dichlorobenzene [128], ATP [119,120] and 1-methyl-1-propylpiperidinium bis(trifluoromethylsulfonyl)imide [68] are utilized as sources to prepare chloride-, phosphorus-and fluoride-functionalized GQDs, respectively. The dimensions and heights of graphene sheets in the obtained GQDs range from 1.5 to 100 nm and 0.5 to 5 nm, respectively.…”

“…In addition to N and S, other heteroatoms have also been successfully doped in GQDs to modulate their photoluminescence properties and expand their applications [128]. Sun et al [158] successfully synthesized fluorinated GQDs (GQDs-F) using fluorinated graphene oxide as starting materials through combining a microwave-assisted technique with a hydrothermal treatment strategy.…”

Quantum size effect of poly(o-phenylenediamine) quantum dots: From controllable fabrication to tunable photoluminescence properties

“…It deserved to note that the band gap of all these quantum dots are larger than oligomers. The change of band gap can be due to the quantum size effect in these quantum dots like semiconductor quantum dots [1][2][3][4][75][76][77].…”

Synthesis of photoluminescent o-phenylenediamine–m-phenylenediamine copolymer nanospheres: An effective fluorescent sensing platform for selective and sensitive detection of chromium(VI) ion

“…Compared with other polymer dots (Pdots) which primarily consist of π-conjugated polymers, fluorescent copolymer dots could be prepared easily, low cost and low cytotoxicity, so it obtain considerable research in various fields [9][10][11][12]. Wu et al reported highly fluorescent semiconducting polymer dots and applied them to biology and medicine [13].…”