Integration of Fullerenes as Electron Acceptors in 3D Graphene Networks: Enhanced Charge Transfer and Stability through Molecular Design

Abstract

Here, we report a concept that allows the integration of the characteristic properties of [60]­fullerene in 3D graphene networks. In these systems, graphene provides high electrical conductivity and surface area while fullerenes add high electron affinity. We use molecular design to optimize the interaction between 3D graphene networks and fullerenes, specifically in the context of stability and charge transfer in an electrochemical environment. We demonstrated that the capacity of the 3D graphene network is significantly improved upon the addition of C60 and C60 monoadducts by providing additional acceptor states in the form of low-lying lowest unoccupied molecular orbitals of C60 and its derivative. Guided by experimental results and first-principles calculations, we synthesized and tested a C60 monoadduct with increased stability by strengthening the 3D graphene–C60 van-der-Waals interactions. The synthesis method and stabilization strategy presented here is expected to benefit the integration of graphene–C60 hybrid materials in solar cell and charge storage applications.

Carbon Nanohybrids for Advanced Electronic Applications

“…[ 72,84 ] However, 3D fullerenes are carbon allotropes and therefore typically exhibit unique electron transfer (ET) properties. [ 85–87 ] There have been numerous research reports on photovoltaic systems based on fullerenes, and their derivatives as acceptors have been investigated. [ 88–91 ] Fullerenes in ET have small reorganization energies and remarkable acceleration abilities of photoinduced charge separations.…”

“…Cerón et al synthesized the methano derivative phenylamine‐C 60 (PA‐C 60 ) before physisorbing on 3D mesoporous graphene macroassemblies (GMAs) to suppress the formation of clusters ( Figure a). [ 85 ] The capacity of the 3D graphene network was also significantly improved on the addition of C 60 by providing additional acceptor states (Figure 6b). [ 85 ] Remarkably, the functionalization with PA‐C 60 increased the gravimetric peak current density of the GMA electrode, from 272.2 to 548.6 mA g −1 , indicating that functionalization of C 60 is an effective strategy to decrease cluster formation and increase fullerene solubility (Figure 6c).…”

“…[ 85 ] The capacity of the 3D graphene network was also significantly improved on the addition of C 60 by providing additional acceptor states (Figure 6b). [ 85 ] Remarkably, the functionalization with PA‐C 60 increased the gravimetric peak current density of the GMA electrode, from 272.2 to 548.6 mA g −1 , indicating that functionalization of C 60 is an effective strategy to decrease cluster formation and increase fullerene solubility (Figure 6c). [ 85 ] In addition, GMA–PA–C 60 shows a significantly high cycling stability compared with GMA–C 60 when only one electron per fullerene molecule is introduced to the system (Figure 6d).…”

“…[ 85 ] Remarkably, the functionalization with PA‐C 60 increased the gravimetric peak current density of the GMA electrode, from 272.2 to 548.6 mA g −1 , indicating that functionalization of C 60 is an effective strategy to decrease cluster formation and increase fullerene solubility (Figure 6c). [ 85 ] In addition, GMA–PA–C 60 shows a significantly high cycling stability compared with GMA–C 60 when only one electron per fullerene molecule is introduced to the system (Figure 6d). [ 85 ] Moreover, Chakravarty et al investigated the electronic structure of the porous graphene–fullerene (PG–C 60 ) nanocomposite for determining the efficacy in solar cell and optoelectronic applications.…”

“…[ 85 ] In addition, GMA–PA–C 60 shows a significantly high cycling stability compared with GMA–C 60 when only one electron per fullerene molecule is introduced to the system (Figure 6d). [ 85 ] Moreover, Chakravarty et al investigated the electronic structure of the porous graphene–fullerene (PG–C 60 ) nanocomposite for determining the efficacy in solar cell and optoelectronic applications. [ 146 ] The unit cell of the PG is defined by the pore size (S) and neck width (L), as [S,L].…”