Chemical functionalization and characterization of graphene-based materials

Abstract

Graphene-based materials (GBMs), with graphene, their most known member, at the head, constitute a large family of materials which has aroused the interest of scientists working in different research fields such as chemistry, physics, or materials science, to mention a few, arguably as no other material before. In this review, we offer a general overview on the most relevant synthetic approaches for the covalent and non-covalent functionalization and characterization of GBMs. Moreover, some representative examples of the incorporation into GBMs of electroactive units such as porphyrins, phthalocyanines, or ferrocene, among others, affording electron donor-acceptor (D-A) hybrids are presented. For the latter systems, the photophysical characterization of their ground- and excited-state features has also been included, paying particular attention to elucidate the fundamental dynamics of the energy transfer and charge separation processes of these hybrids. For some of the presented architectures, their application in solar energy conversion schemes and energy production has been also discussed.

Direct estimation of the transfer integral for photoinduced electron transfer from TD DFT calculations

“…In Table 1, we also compare electronic couplings estimated using eqn (2) with the reference data obtained by the FCD method. 6,7 As seen there is good agreement between the obtained and the FCD values.…”

“…[1][2][3][4][5][6][7][8] . The ET rate is controlled by electronic coupling of the initial and final states.…”

Charged Carbon Nanomaterials: Redox Chemistries of Fullerenes, Carbon Nanotubes, and Graphenes

“…Noncovalent interactions, such as π−π stacking of CNT/pyrene, are sometimes also described as functionalizations; however, while these interactions are undoubtedly useful in many contexts (and have been reviewed previously 319,320 ), here functionalization will only be used to describe the covalent attachment of an external moiety. Functionalization of (uncharged) fullerenes, 321,322 SWCNTs, 323,324 and graphene 325,326 have each been extensively reviewed previously. The most common types of functionalization rely on heavy oxidation to introduce polar groups, usually through the formation of sp 3 or edge-type defects.…”

Exploring Tetrathiafulvalene–Carbon Nanodot Conjugates in Charge Transfer Reactions

“…By virtue of variable supramolecular forces either electron donors or acceptors have been non-covalently combined with CNDs. [27] They have been successfully used for preparing photoinduced electron transfer systems [28] as well as solar energy conversion devices. [25] Thec ovalent approach to CNDs functionalization is particularly interesting as it enables the introduction of multiple photo-or electroactive units in the form of stable nanoconjugates.I nt his context, we have explored the preparation of novel CND-based electron donor-acceptor systems.Inparticular,wehave covalently linked aphoto-and redox-active molecular building block, namely p-extended tetrathiafulvalene (exTTF), [26] to CNDs materials.exTTFs are pro-aromatic electron donors.U nlike porphyrins,t hey undergo ar emarkable gain of aromaticity and planarity upon oxidation, forming stable one-electron and two-electron oxidized species at relatively low oxidation potentials.C onsidering these features,e xTTFs have been widely used to form electroactive architectures when linked to fullerenes, carbon nanotubes,a nd graphene.…”