Long-wavelength, multicolor, and white-light emitting carbon-based dots: Achievements made, challenges remaining, and applications

Shamsipur, Mojtaba; Barati, Ali; Karami, Sara

doi:10.1016/j.carbon.2017.08.072

Cited by 263 publications

(153 citation statements)

References 248 publications

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“…Carbon dots (CDs), as a new kind of luminescent material, have drawn extensive attention during the past decade . Scientists have made great efforts to develop this material, and now, CDs can be easily fabricated from abundant low‐cost sources with green methods, and exhibit excellent photostability and low cytotoxicity, especially the amazing photoluminescence (PL) .…”

Section: Introductionmentioning

confidence: 99%

Solvent‐Controlled Synthesis of Highly Luminescent Carbon Dots with a Wide Color Gamut and Narrowed Emission Peak Widths

Ding

Wei

Zhang

et al. 2018

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Carbon dots (CDs) have tremendous potential applications in bioimaging, biomedicine, and optoelectronics. By far, it is still difficult to produce photoluminescence (PL) tunable CDs with high quantum yield (QY) across the entire visible spectrum and narrow the emission peak widths of CDs close to those of typical quantum dots. In this work, a series of CDs with tunable emission from 443 to 745 nm, quantum yield within 13-54%, and narrowed full width at half maximum (FWHM) from 108 to 55 nm, are obtained by only adjusting the reaction solvents in a one-pot solvothermal route. The distinct optical features of these CDs are based on their differences in the particle size, and the content of graphitic nitrogen and oxygen-containing functional groups, which can be modulated by controlling the dehydration and carbonization processes during solvothermal reactions. Blue, green, yellow, red, and even pure white light emitting films (Commission Internationale de L'Eclairage (CIE)= 0.33, 0.33, QY = 39%) are prepared by dispersing one or three kinds of CDs into polyvinyl alcohol with appropriate ratios. The near-infrared emissive CDs are excellent fluorescent probes for both in vitro and in vivo bioimaging because of their high QY in water, long-term stability, and low cytotoxicity.

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Section: Introductionmentioning

confidence: 99%

Solvent‐Controlled Synthesis of Highly Luminescent Carbon Dots with a Wide Color Gamut and Narrowed Emission Peak Widths

Ding

Wei

Zhang

et al. 2018

Small

478

339

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“…[2,11,[13][14][15][16]21] Carbon dots (CDs), an ewly emerged luminescent nanomaterial, have received widespread interest and have been successfully employed in many fields of research thanks to their superior optical properties,e xcellent biocompatibility, and cost-effective preparation. [22][23][24][25] Specifically,the RTPand delayed fluorescence (FL) properties of CDs have been discovered recently,but are only observable by embedding or immobilizing in certain matrices (e.g., poly(vinyl alcohol) (PVA), polyurethane,u rea/biuret, or zeolites). [26][27][28][29][30][31][32][33] Inspired by these findings and the general requirements for producing effective RTP, we propose that it might be possible to prepare RTPC Ds directly if the following conditions are complied with:1 )CDs should be mostly amorphous polymer-like structures which hopefully will behave as matrices to embed and immobilize luminogens;2 )the interior of CDs should contain functional groups that could form hydrogen bonds, for further stabilization of excited triplet species;a nd 3) elements that favoring n!p*t ransitions (e.g.,N ,P ,a nd halogens) should be doped in CDs,t ofacilitate the ISC process and consequently to effectively populate triplet excitons.…”

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confidence: 99%

Facile, Quick, and Gram‐Scale Synthesis of Ultralong‐Lifetime Room‐Temperature‐Phosphorescent Carbon Dots by Microwave Irradiation

et al. 2018

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Long-lifetime room-temperature phosphorescence (RTP) materials are important for many applications, but they are highly challenging materials owing to the spin-forbidden nature of triplet exciton transitions. Herein, a facile, quick and gram-scale method for the preparation of ultralong RTP (URTP) carbon dots (CDs) was developed via microwave-assisted heating of ethanolamine and phosphoric acid aqueous solution. The CDs exhibit the longest RTP lifetime, 1.46 s (more than 10 s to naked eye) for CDs-based materials to date. The doping of N and P elements is critical for the URTP which is considered to be favored by a n→π* transition facilitating intersystem crossing (ISC) for effectively populating triplet excitons. In addition, possibilities of formation of hydrogen bonds in the interior of the CDs may also play a significant role in producing RTP. Potential applications of the URTP CDs in the fields of anti-counterfeiting and information protection are proposed and demonstrated.

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“…[2,4] Various chemical groups are found to effectively enhance the photoluminescent efficiencies of the pristine graphene nanostructures upon surface attachment. [1,[8][9][10][11] The character of chemical groups under photoexcitation is of fundamental importance for the tuning of the photophysics of relevant materials. [1,[8][9][10][11] The character of chemical groups under photoexcitation is of fundamental importance for the tuning of the photophysics of relevant materials.…”

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confidence: 99%

Nonradiative Excited‐State Decay via Conical Intersection in Graphene Nanostructures

et al. 2019

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Chemical groups are known to tune the luminescent efficiencies of graphene-related nanomaterials, but some species, including the epoxide group (À COCÀ ), are suspected to act as emissionquenching sites. Herein, by performing nonadiabatic excitedstate dynamics simulations, we reveal a fast (within 300 fs) nonradiative excited-state decay of a graphene epoxide nanostructure from the lowest excited singlet (S 1 ) state to the ground (S 0 ) state via a conical intersection (CI), at which the energy difference between the S 1 and S 0 states is approximately zero. This CI is induced after breaking one CÀ O bond at the À COCÀ moiety during excited-state structural relaxation. This study ascertains the role of epoxide groups in inducing the nonradiative recombination of the excited electron-hole, providing important insights into the CI-promoted nonradiative deexcitations and the luminescence tuning of relevant materials. In addition, it shows the feasibility of utilizing nonadiabatic excited-state dynamics simulations to investigate the photophysical processes of the excited states of graphene nanomaterials. Computational DetailsThe ground-and excited-state properties were studied by density functional theory (DFT) and time-dependent DFT (TD-DFT), respectively, as implemented by the Gaussian 09[a] S.

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Long-wavelength, multicolor, and white-light emitting carbon-based dots: Achievements made, challenges remaining, and applications

Cited by 263 publications

References 248 publications

Solvent‐Controlled Synthesis of Highly Luminescent Carbon Dots with a Wide Color Gamut and Narrowed Emission Peak Widths

Solvent‐Controlled Synthesis of Highly Luminescent Carbon Dots with a Wide Color Gamut and Narrowed Emission Peak Widths

Facile, Quick, and Gram‐Scale Synthesis of Ultralong‐Lifetime Room‐Temperature‐Phosphorescent Carbon Dots by Microwave Irradiation

Nonradiative Excited‐State Decay via Conical Intersection in Graphene Nanostructures

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