Azo addition to exfoliated graphene: a facile and high yield route to functionalized graphene

Abstract

A facile and high yield method for the covalent functionalization of graphene through the free radical addition of a commercially available polymerization initiator, 2,29-azobisisobutyronitrile (AIBN), has been successfully realized. The obtained material was determined to have 1 isobutyronitrile group substituent per 50 carbon atoms.

A DFT Study on Electronic and Structural Properties of Graphene Nanoribbons

“…AGNR [3,1] have roughly the same Eg comparing with C60 and PCBM. AGNR [3,2], [4,2], and [5,2] exhibit an increase in HOMO energies, and decrease in LUMO energies, yielding a reduction of Eg. Electronic properties of these AGNRs show the considerable difference with those of C60 and PCBM.…”

“…The larger value of Eg in the case of AGNR [4,7] is the result of their larger deviation from 2D graphene. In the case of narrower AGNR [3,7], we can see even more energy shifts: ~ 0.25 eV for HOMO and 0.24 eV for LU-MO. This leads to the substantial decrease in Eg, alt-hough it remains a non-zero value (0.316 eV) (Fig.…”

“…Further elongation of AGNRs leads to the gradual increase in HOMO and decrease in LUMO energies. The longest AGNRs [3,7], [4,7], and, at a larger degree, [5,7] resemble properties of 2D graphene, and it is of no use to 04052-3 employ them in pristine form as electron acceptors in the OSCs. These data witness that despite the considerable alternation in energies of the frontier orbitals, the present model AGNRs could not be effective equivalents of widely used fullerene derivatives to substitute them in the design of OSCs.…”

“…However, the direct substitution of PCBM on short AGNRs does not provide the necessary level of power conversion, because of non-optimal mutual arrangement of the HOMO and LUMO energy levels. [3,7], AGNR [4,7], and AGNR [5,7]. Hydrogen atoms omitted for clarity At the same time, a careful adjustment of length can help researchers in obtaining AGNRs with 'fine-tuned' properties.…”

“…Graphene, a perfect single layer of carbon atoms that are bonded together in a hexagonal honeycomb lattice, has become a focus of attention from both experimentalists and theorists since the discovery of Geim and Novoselov [1]. Unique properties of graphene predetermine its great influence on nanotechnologies [2][3][4][5][6][7][8]. However, the absence of a band gap of graphene sets the limits on the efficiency of graphene-based electronic and optoelectronic switching devices.…”