Designing Cascades of Electron Transfer Processes in Multicomponent Graphene Conjugates

Abstract

A novel family of nanocarbon‐based materials was designed, synthesized, and probed within the context of charge‐transfer cascades. We integrated electron‐donating ferrocenes with light‐harvesting/electron‐donating (metallo)porphyrins and electron‐accepting graphene nanoplates (GNP) into multicomponent conjugates. To control the rate of charge flow between the individual building blocks, we bridged them via oligo‐p‐phenyleneethynylenes of variable lengths by β‐linkages and the Prato–Maggini reaction. With steady‐state absorption, fluorescence, Raman, and XPS measurements we realized the basic physico‐chemical characterization of the photo‐ and redox‐active components and the multicomponent conjugates. Going beyond this, we performed transient absorption measurements and corroborated by single wavelength and target analyses that the selective (metallo)porphyrin photoexcitation triggers a cascade of charge transfer events, that is, charge separation, charge shift, and charge recombination, to enable the directed charge flow. The net result is a few nanosecond‐lived charge‐separated state featuring a GNP‐delocalized electron and a one‐electron oxidized ferrocenium.

Photon‐ and Charge‐Management in Advanced Energy Materials: Combining 0D, 1D, and 2D Nanocarbons as well as Bulk Semiconductors with Organic Chromophores

“…Of great importance was the fact that cascades of charge‐shift events generated long‐lived GNP •− ZnPFc •+ charge‐separated states with lifetimes in the nanosecond time range featuring a GNP‐delocalized electron and the one‐electron oxidized form of Fc as one of the final products. [ 122 ]…”

“…Of great importance was the fact that cascades of charge-shift events generated long-lived GNP •− ZnPFc •+ charge-separated states with lifetimes in the nanosecond time range featuring a GNPdelocalized electron and the one-electron oxidized form of Fc as one of the final products. [122] In short, controlling 2D GNPs in electron donor-acceptor conjugates has led to the exploration of 2D CNDs and 2D HBCs. Among them, only 2D GNPs and partially amorphous 2-D CNDs when linked to MPs have participated in electron transfer reactions-Scheme 4.…”

“…ZnP •− GNP FcZnP •+ GNP •− Fc •+ ZnP •− GNP FcZnP •+ GNP •− /Fc •+ ZnPGNP •− [120-122] ZnP •− GNP FcZnP •+ GNP •− Fc •+ ZnP •− GNP FcZnP •+ GNP •− /Fc •+ ZnPGNP •−[120][121][122] …”

Functionalization of Gold Nanoparticles with Ru-Porphyrin and Their Selectivity in the Oligomerization of Alkynes

“…Hybrid architectures composed of both porphyrin/metalloporphyrin and different materials such as organic or inorganic nanoparticles [ 14 , 15 ] and carbon-based-nanomaterials [ 16 ], obtained by a bottom-up approach, are well suited for the formation of functional nanostructures [ 17 ] that display structural control and synergic functionalities. These preparation methods will result in the formation of unique materials with properties fundamental for the development of compounds that find wide space in several fields such as optics [ 18 , 19 , 20 , 21 , 22 ]; electronics [ 23 ]; photodynamic therapy [ 24 ]; materials able to enhance light absorption [ 25 ]; and catalysis [ 26 ].…”

Nonlinear Optical Properties of Porphyrin, Fullerene and Ferrocene Hybrid Materials

“…In Fc-P-C60 triads a high charge delocalization of the π-electrons between the donor Fc and the acceptor C60 moieties is reached by linking them to the 2,12 β-pyrrolic positions of P through an ethynyl or an ethynylphenyl spacer [46], thus constituting an efficient approach to the modulation of electron donor-acceptor interactions to realize hybrid materials [47][48][49][50][51][52].…”