Fluorescence behavior of nanoconjugates of graphene quantum dots and zinc phthalocyanines

Achadu, Ojodomo J.; Uddin, Imran; Nyokong, Tebello

doi:10.1016/j.jphotochem.2015.11.006

Cited by 56 publications

(22 citation statements)

References 40 publications

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“…With their unique optical properties, QDs are frequently used in energy transfer studies, especially with phthalocyanines and biomolecules through the formation of QD– phthalocyanine‐ or biomolecule‐conjugated systems. [ 12 ] An important advantage of QD‐phthalocyanine‐conjugated systems is the relative ease of hybrid production. Heterocyclic rings containing suitable end groups can spontaneously form complexes in solution with QD structures.…”

Section: Introductionmentioning

confidence: 99%

Effect of heteroatom‐doped carbon quantum dots on the red emission of metal‐conjugated phthalocyanines through hybridization

et al. 2021

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Quantum dots (QDs) are significant fluorescent materials for energy transfer studies with phthalocyanines (Pcs) and phthalocyanine (Pc)‐like biomolecules (such as chlorophylls). Carbon‐based QDs, especially, have been used in numerous studies concerning energy transfer with chlorophylls, but the numbers of studies concerning energy transfer between phthalocyanines and carbon‐based QDs are limited. In this study, peripherally, hydroxythioethyl terminal group substituted metal‐free phthalocyanine (H2Pc) and zinc phthalocyanine (ZnPc) were noncovalently (electrostatic and/or π–π interaction) attached to carbon QDs containing boron and nitrogen to form QD‐Pc nanoconjugates. The QD‐Pc conjugates were characterized using different spectroscopic techniques (Fourier transform infrared spectroscopy and transmission electron microscopy). The absorption and fluorescence properties of QD‐Pc structures in solution were studied. It was found that the quantum yields of the QDs slightly decreased from 30% to 25% upon doping the QDs with heteroatoms B and N. Förster resonance energy transfer efficiency was calculated as 33% for BCN‐QD/ZnPc. For the other conjugates, almost no energy transfer from QDs to Pc cores was observed. It was shown that the energy transfer between QDs to Pc cores was completely different from the energy transfer between QDs and photosynthetic pigments, and therefore we concluded that heteroatom doping in the QD structure and the existence of zinc metal in the phthalocyanine structure is obligatory for an efficient energy transfer.

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Section: Introductionmentioning

confidence: 99%

Effect of heteroatom‐doped carbon quantum dots on the red emission of metal‐conjugated phthalocyanines through hybridization

et al. 2021

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“…We have previously reported on the conjugates of GQDs with MPcs for optical sensing , this work present the first study of the electrocatalytic behaviour of these conjugates. CoPc derivatives are employed since MPcs containing Co central metal are known to exhibit high catalytic activity for various reactions including the electrooxidation of hydrazine .…”

Section: Introductionmentioning

confidence: 70%

Effects of Substituents on the Electrocatalytic Activity of Cobalt Phthalocyanines when Conjugated to Graphene Quantum Dots

2017

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We report on the π–π interactions between graphene quantum dots (GQDs) and the following cobalt phthalocyanine derivatives: cobalt monocarboxyphenoxy phthalocyanine (complex 1), cobalt tetracarboxyphenoxyphthalocyanine (complex 2), and cobalt tetraaminophenoxy phthalocyanine (complex 3). The conjugates (conj) with GQDs are represented as 1@GQDs(conj), 2@GQDs(conj) and 3@GQDs(conj), respectively. The resulting phthalocyanine/GQDs conjugates were adsorbed on containing a glassy carbon electrode (GCE) using the drop and dry method. We explore the electrochemical properties of phthalocyanines functionalized with both electron withdrawing groups and electron donating groups when non‐covalently linked to the π‐electron rich graphene quantum dots. GCE/3, GCE/2@GQDs(conj) and GCE/1@GQDs(conj) had the lowest limits of detection (LOD). Sequentially modified electrodes showed less favourable detection limits compared to the conjugates.

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“…Conversely, as the electronic properties of the macrocycle are not deeply modified by the graphene substrate, such systems should retain the remarkable intrinsic properties of the macrocyclic complex. Indeed such hybrid materials have been actively explored for catalytic, (bio)‐sensing properties, or optical properties …”

Section: Discussionmentioning

confidence: 99%

“…Due to the absence of band gap around the Fermi level, numerous approaches have been developed using molecular doping to tailor the transport properties of graphene‐based devices for nano‐electronic and photonic applications . More generally the chemical functionalization of graphene is crucial for a variety of technological applications including novel electronics or spintronic devices, photodetectors, catalysis, molecular sensors, field‐effect transistors, new energy materials, or novel hybrid species with original properties . In this context, the noncovalent functionalization based on π –π stacking is usually preferred to covalent treatments which may degrade the aromaticity of the carbon surface by creating sp 3 carbon defects, thus, lowering the high carrier mobility …”

Section: Introductionmentioning

confidence: 99%

Combined molecular and periodic DFT analysis of the adsorption of co macrocycles on graphene

2017

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The molecular doping of graphene with π-stacked conjugated molecules has been widely studied during the last 10 years, both experimentally or using first-principle calculations, mainly with strongly acceptor or donor molecules. Macrocyclic metal complexes have been far less studied and their behavior on graphene is less clear-cut. The present density functional theory study of cobalt porphyrin and phthalocyanine adsorbed on monolayer or bilayer graphene allows to compare the outcomes of two models, either a finite-sized flake of graphene or an infinite 2D material using periodic calculations. The electronic structures yielded by both models are compared, with a focus on the density of states around the Fermi level. Apart from the crucial choice of calculation conditions, this investigation also shows that unlike strongly donating or accepting organic dopants, these macrocycles do not induce a significant doping of the graphene sheet and that a finite size model of graphene flake may be confidently used for most modeling purposes. © 2017 Wiley Periodicals, Inc.

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Fluorescence behavior of nanoconjugates of graphene quantum dots and zinc phthalocyanines

Cited by 56 publications

References 40 publications

Effect of heteroatom‐doped carbon quantum dots on the red emission of metal‐conjugated phthalocyanines through hybridization

Effect of heteroatom‐doped carbon quantum dots on the red emission of metal‐conjugated phthalocyanines through hybridization

Effects of Substituents on the Electrocatalytic Activity of Cobalt Phthalocyanines when Conjugated to Graphene Quantum Dots

Combined molecular and periodic DFT analysis of the adsorption of co macrocycles on graphene

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