Soft-template synthesis of nitrogen-doped carbon nanodots: tunable visible-light photoluminescence and phosphor-based light-emitting diodes

Do, Sungan; Kwon, Woosung; Rhee, Shi‐Woo

doi:10.1039/c4tc00090k

Cited by 53 publications

(48 citation statements)

References 29 publications

(38 reference statements)

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“…The QYs were remarkably reduced by doping, presumably due to the fact that heteroatoms would reduce the crystallinity of the carbon core to generate defective sites (radical, etc. ), resulting in at least partially quenching PL of our CNDs . This was also identified by time‐correlated single photon counting (TCSPC) data (Figure S13, Supporting Information).…”

Section: Resultssupporting

confidence: 71%

“…It has been reported that the electronic structure of CNDs originates from their polyaromatic carbon domains, defective states, and surface states, presumably due to auxochromic effect . Currently, doping heteroatoms, especially nitrogen and/or sulfur, in a carbon framework has been found to be an attractive strategy to control photoluminescence (PL) of CNDs . Such dopants can be considered to generate defective states, where their different electronegativity, lone pairs of electrons, etc., change the electronic structure of CNDs.…”

Section: Introductionmentioning

confidence: 99%

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N,S‐Induced Electronic States of Carbon Nanodots Toward White Electroluminescence

Kwon

Kim

et al. 2015

Advanced Optical Materials

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Generally, the optical properties of CNDs are directly related to their electronic structure. It has been reported that the electronic structure of CNDs originates from their polyaromatic carbon domains, defective states, and surface states, presumably due to auxochromic effect. [ 7,[15][16][17] Currently, doping heteroatoms, especially nitrogen and/or sulfur, in a carbon framework has been found to be an attractive strategy to control photoluminescence (PL) of CNDs. Such dopants can be considered to generate defective states, where their different electronegativity, lone pairs of electrons, etc., change the electronic structure of CNDs. Many research groups have attempted to synthesize a variety of heteroatom-doped CNDs with distinguished optical properties. For example, Dong's group produced highly luminescent nitrogen and sulfur co-doped carbon-based dots through a one-step hydrothermal treatment using L -cysteine and citric acid as a dopant and carbon precursor, respectively. [ 37 ] In another study, Li et al. reported a facile method to prepare sulfur-doped graphene quantum dots for tuning their electronic structure by using sulfuric acid and fructose as a sulfur and carbon precursor, respectively. [ 38 ] Although these attempts have proven themselves promising; however, there have been limitations on the control of a degree of doping because heating a physical mixture of two separated precursors that have different structures and reactivity cannot guarantee the formation of desired chemical bondings between them. In this case, the bonding state of dopant atoms cannot be clear to make their roles in CNDs ambiguous. Thus, it is necessary to use a new precursor carrying both dopant and carbon atoms to not only guarantee effi cient doping but also examine the effect of doping on the optical properties of CNDs in a molecular level.Herein, we now present the synthesis of nitrogen and sulfur-doped CNDs (denoted as N-CNDs and S-CNDs, respectively) with single molecular precursors: ethylenediamine-N,N ′-diacetic acid (EDDA) and 2,2′-(ethylenedithio)diacetic acid (ETDA), respectively. [ 7,12 ] Our doping would lead to signifi cant changes in the electronic structure of CNDs and give rise to broad light absorption and strong PL in a long-wavelength visible light region. We fi nally demonstrated light-emitting diodes (LEDs) with our CNDs to show the effects of doping on their electronic structure and related electroluminescence (EL). OurIn this work, nitrogen and sulfur-doped carbon nanodots (CNDs) have been synthesized from ethylenediamine-N,N′ -diacetic acid and 2,2 ′ -(ethylenedithio) diacetic acid, respectively. The method used in this work features the use of "single" molecular precursors that contain both carbon and dopant atoms, which allows examining the effects of doping in a molecular level. The effects of doping on the electronic structure of CNDs could be examined by a series of spectroscopic measurements including UV-vis absorption and photoluminescence. It is found that doping gives rise to new light abs...

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Section: Resultssupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

N,S‐Induced Electronic States of Carbon Nanodots Toward White Electroluminescence

Kwon

Kim

et al. 2015

Advanced Optical Materials

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“…[17,18] CNDs are strong light emitters that feature broad and, more importantly, tunable absorptions throughout the visible range of the solar spectrum. [19] Thebasis for acomprehensive understanding of the CNDs photophysical properties has been laid out in an umber of combined experimental and/or theoretical studies. [20] Both bottom-up and top-down approaches to the synthesis of CNDs have been described in recent years.Thermal or microwave-assisted and electrochemical deposition syntheses are prominent examples for bottom-up approaches, while synthetic strategies,s uch as the oxidation of graphite and cage opening of fullerenes,t ypify top-down strategies.…”

Section: Introductionmentioning

confidence: 99%

Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring Perylenediimides

et al. 2015

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We describe the formation of charge-transfer complexes that feature electron-donating carbon nanodots (CND) and electron-accepting perylenediimides (PDI). The functionalities of PDIs have been selected to complement those of CNDs in terms of electrostatic and π-stacking interactions based on oppositely charged ionic head groups and extended π-systems, respectively. Importantly, the contributions from electrostatic interactions were confirmed in reference experiments, in which stronger interactions were found for PDIs that feature positively rather than negatively charged head groups. The electronic interactions between the components in the ground and excited state were characterized in complementary absorption and fluorescence titration assays that suggest charge-transfer interactions in both states with binding constants on the order of 8×10(4) M(-1) (25 L g(-1) ). Selective excitation of the two components in ultrafast pump probe experiments gave a 210 ps lived charge-separated state.

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“…Specific technological applications require particular surface activity of the nanomaterials, as for instance in the ink-jet printing of nanomaterials for surface coating of electronic/photonic devices [12]. In this case, it is highly desirable to obtain nanoparticles without any precursor residues and stabilizing ligands.…”

Section: Introductionmentioning

confidence: 99%

Laser assisted synthesis of carbon nanoparticles with controlled viscosities for printing applications

Bagga

McCann

Wang

2015

Journal of Colloid and Interface Science

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High-quality carbon nanoparticles with controlled viscosity and high aqueous stability were prepared by liquid-phase laser ablation of a graphite target in deionized water. The size distribution was found to vary from 5 nm to 50 nm with mean size of 18 nm, in the absence of any reducing chemical reagents. Efficient generation of short chain polyynes was recorded for high laser repetition rates. Homogeneous and stable nanoparticle suspensions with viscosities ranging from 0.89 to 12 mPa.s were obtained by suspending the nanoparticles in different solvent mixtures such as glycerol-water and isopropanol-water. Optical properties were investigated by absorption and photoluminescence spectroscopy. Raman spectroscopy confirmed graphitic-like structure of nanoparticles and the surface chemistry was revealed by Fouriertransform infrared spectroscopy demonstrating sufficient electrostatic stabilization to avoid particle coagulation or flocculation. This paper present an exciting alternative method to engineer carbon nanoparticles and their potential use as a ligand-free nano-ink for ink jet printing (jetting) applications.

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Soft-template synthesis of nitrogen-doped carbon nanodots: tunable visible-light photoluminescence and phosphor-based light-emitting diodes

Cited by 53 publications

References 29 publications

N,S‐Induced Electronic States of Carbon Nanodots Toward White Electroluminescence

N,S‐Induced Electronic States of Carbon Nanodots Toward White Electroluminescence

Carbon Nanodots: Supramolecular Electron Donor–Acceptor Hybrids Featuring Perylenediimides

Laser assisted synthesis of carbon nanoparticles with controlled viscosities for printing applications

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