Donor–acceptor graphene-based hybrid materials facilitating photo-induced electron-transfer reactions

Abstract

SummaryGraphene research and in particular the topic of chemical functionalization of graphene has exploded in the last decade. The main aim is to increase the solubility and thereby enhance the processability of the material, which is otherwise insoluble and inapplicable for technological applications when stacked in the form of graphite. To this end, initially, graphite was oxidized under harsh conditions to yield exfoliated graphene oxide sheets that are soluble in aqueous media and amenable to chemical modifications due to the presence of carboxylic acid groups at the edges of the lattice. However, it was obvious that the high-defect framework of graphene oxide cannot be readily utilized in applications that are governed by charge-transfer processes, for example, in solar cells. Alternatively, exfoliated graphene has been applied toward the realization of some donor–acceptor hybrid materials with photo- and/or electro-active components. The main body of research regarding obtaining donor–acceptor hybrid materials based on graphene to facilitate charge-transfer phenomena, which is reviewed here, concerns the incorporation of porphyrins and phthalocyanines onto graphene sheets. Through illustrative schemes, the preparation and most importantly the photophysical properties of such graphene-based ensembles will be described. Important parameters, such as the generation of the charge-separated state upon photoexcitation of the organic electron donor, the lifetimes of the charge-separation and charge-recombination as well as the incident-photon-to-current efficiency value for some donor–acceptor graphene-based hybrids, will be discussed.

In‐Situ covalent synthesis of gold nanorods on GO surface as ultrasensitive Raman probe

“…The GO‐AuNRs hybrid was prepared via three‐step process. In the first step, water dispersible graphite oxide was prepared from natural graphite powder by a modified Hummers and Offeman ' s method . The second step is to synthesize thiolated graphene oxide (GO‐O‐SH).…”

“…In the first step, water dispersible graphite oxide was prepared from natural graphite powder by a modified Hummers and Offeman ' s method. [28][29][30][31][32][33][34][35][36] The second step is to synthesize thiolated graphene oxide (GO-O-SH). The pH of GO solution (1.6 mg/ml −1 ) was adjusted to about 9.5 by adding 10 wt % NaOH solutions.…”

Covalently Modified Graphenes in Catalysis, Electrocatalysis and Photoresponsive Materials

“…Pc [82,83,116,117] or porphyrin [87][88][89]118] have been the preferred light responsive units among other possibilities. [96,[119][120][121]192] For instance, as eries of metal or metal-free Pcs have been covalently attached to high quality Ga nd their behaviora s electron acceptors or even electron donors studied. The G samples wereo btained from graphite by liquid-phasee xfoliation using solvents such as NMP [82] or o-dichlorobenzene.…”

Fullerene grafted graphene oxide with effective charge transfer interactions

“…The sp 2 hybridised carbon pattern extending in two dimension helps in introducing different types of functional groups covalently by addition or substitution reactions. Attachment of small/large functional molecules like, diazonium salts, alkyl isocyanates, polymers, porphyrin and also bulky fullerene via substitution or additions reactions on GO have been reported to exploit the advantages by altering its properties and finding potential applications in several areas [7,8,9,10,11,12,13,14,15]. Some research has also been carried out to attach bulky fullerene molecules (like polyhydroxy fullerene, pyrrolidine fullerene, methanofullerene etc.)…”