Synthesis and properties of multi-functionalized graphene quantum dots with tunable photoluminescence and hydrophobicity from asphaltene and its oxidized and reduced derivatives

Aghajamali, Maryam; Vieira, Mariana A.; Firouzi-Haji, Razieh; Cui, Kai; Cho, Jae-Young; Bergren, Adam Johan; Meldrum, A.

doi:10.1039/d2na00445c

Cited by 15 publications

(11 citation statements)

References 72 publications

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“…Other samples were previously characterized by TEM analysis. 29 When applied to clean glass surfaces, the GQDs had an obvious effect on the water contact angle (Figure 3), which increased from 52 to 102°after a light spray-coating of type-AC particles (Figure 3a,b). Subsequently washing the hydrophobic surface three times in water had negligible effects on the contact angle, consistent with the GQDs being adsorbed onto the glass surfaces.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…Brightfield transmission electron microscopy (TEM) imaging indicated the presence of small particles (range 3–15, mean 6.4 nm) with 0.27 and 0.35 nm lattice spacings consistent with those of graphene (Figures S1 and S2). Other samples were previously characterized by TEM analysis …”

Section: Resultsmentioning

confidence: 99%

“…0.2 μm Nylon and PTFE syringe filters were supplied by VWR International. The methods employed were modified based on our previous report 29 and are summarized herein. Bitumen from the Alberta oilsands was first mixed with heptane (1 g of bitumen for each 40 mL of solvent), sonicated for 50 min, and allowed to settle for 24 h. Then, 75 vol % of the supernatant filtered using Whatman filter paper #2 and fresh solvent with 10% of the volume of the original solution was added to the mixture.…”

Section: ■ Introductionmentioning

confidence: 99%

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Asphaltene-Derived Graphene Quantum Dots for Controllable Coatings on Glass, Fabrics, and Aerogels

Firouzi-Haji,

Aghajamali,

Hassanzadeh

et al. 2023

ACS Omega

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Section: ■ Results and Discussionmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Asphaltene-Derived Graphene Quantum Dots for Controllable Coatings on Glass, Fabrics, and Aerogels

Firouzi-Haji,

Aghajamali,

Hassanzadeh

et al. 2023

ACS Omega

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“…Asphaltene was first separated from a bitumen sample provided by an oil company in Alberta, following an established procedure , (Figure a). The asphaltene (2 g) was oxidized by nitric acid (7 M, 100 mL) at 75 °C overnight.…”

Section: Methodsmentioning

confidence: 99%

Graphene Quantum Dot Bearing Liquid Droplets for Ultrasensitive Fluorescence-Based Detection of Nitroaromatics

Wang

Firouzi-Haji

Aghajamali

et al. 2022

ACS Appl. Nano Mater.

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Sensing and detecting nitroaromatics (NAs) are essential for environmental, health, and safety reasons. Graphene quantum dots (GQDs) respond to the presence of NAs by a well-understood fluorescence quenching mechanism. However, despite the relative simplicity of fluorescence-based sensing, the limit of detection (LoD) can compare unfavorably with other methods. Here, we show that the LoD for sensors based on GQDs can be lowered by orders of magnitude using a droplet-based analyte partitioning effect. While previous efforts have attempted to improve the intrinsic GQD sensitivity via surface functionalization and size control, we show that a major improvement can be attained by changing from a bulk solution to droplet-based sensing of 2,4-dinitrotoluene and nitrobenzene. Moreover, the method is compatible with sensing from an aqueous solvent and has broader implications for many fluorescence-quenching-based sensing strategies that could benefit from partition-related enhancements.

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“…Comprehensive insight into the mechanisms governing the intriguing optical properties of GQDs is essential for their practical application in optoelectronic devices. For sizes of GQDs of less than 100 nm, quantum confinement and edge effects play a crucial role in deciding their photoluminescence (PL) − and absorption properties. − This has triggered tremendous experimental and theoretical research to selectively regulate the optical characteristics of pristine GQDs through various techniques such as surface functionalization, heteroatom doping, and the introduction of defects , in recent years.…”

Section: Introductionmentioning

confidence: 99%

Edge Modification and Site-Selective Functionalization of Graphene Quantum Dots: A Versatile Technique for Designing Tunable Optoelectronic and Sensing Devices

Basak

Basak²

2023

J. Phys. Chem. A

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This work successfully traces the imprints of zigzag/armchair-edge modification and site-selective functionalization by different chemical species in dictating the structural, electronic, and optical properties of low-symmetry structural isomers of graphene quantum dots (GQDs). Our time-dependent density functional theory-based computations reveal that the electronic band gap reduction is greater for zigzag-edge functionalization than for armchair-edge modification by chlorine atoms. The computed optical absorption profile of functionalized GQDs exhibits an overall red shift with respect to their pristine counterpart, with the shift being more pronounced at higher energies. Markedly, the optical gap energy is regulated more substantially by zigzag-edge chlorine passivation while the armchair-edge chlorine functionalization is more effective in altering the position of the most intense (MI) absorption peak. The MI peak energy is exclusively decided by the significant perturbation in the electron–hole distribution produced by the structural warping of the planar carbon backbone realized by edge-functionalization while the interplay between frontier orbital hybridization and structural distortion governs the energies of the optical gap. In particular, the enhanced tunability range of the MI peak in comparison to the optical gap variation signals that the structural warping plays a more decisive role in modulating the MI peak characteristics. The energy of the optical gap and the MI peak along with the charge-transfer character of the excited states is critically dependent on the electron-withdrawing capability and the site of the functional group. This comprehensive study is extremely crucial for promoting the application of functionalized GQDs in designing highly efficient tunable optoelectronic devices.

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Synthesis and properties of multi-functionalized graphene quantum dots with tunable photoluminescence and hydrophobicity from asphaltene and its oxidized and reduced derivatives

Abstract: Graphene quantum dots with tunable photoluminescence and hydrophobicity were synthesized from an abundant natural carbon source containing nitrogen, sulfur, and oxygen heteroatoms.

Cited by 15 publications

References 72 publications

Asphaltene-Derived Graphene Quantum Dots for Controllable Coatings on Glass, Fabrics, and Aerogels

Asphaltene-Derived Graphene Quantum Dots for Controllable Coatings on Glass, Fabrics, and Aerogels

Graphene Quantum Dot Bearing Liquid Droplets for Ultrasensitive Fluorescence-Based Detection of Nitroaromatics

Edge Modification and Site-Selective Functionalization of Graphene Quantum Dots: A Versatile Technique for Designing Tunable Optoelectronic and Sensing Devices

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