Facile synthesis of analogous graphene quantum dots with sp²hybridized carbon atom dominant structures and their photovoltaic application

Abstract

Graphene quantum dot (GQD) is an emerging class of zero-dimensional nanocarbon material with many novel applications. It is of scientific importance to prepare GQDs with more perfect structures, that is, GQDs containing negligible oxygenous defects, for both optimizing their optical properties and helping in their photovoltaic applications. Herein, a new strategy for the facile preparation of "pristine" GQDs is reported. The method we presented is a combination of a bottom-up synthetic and a solvent-induced interface separation process, during which the target products with highly crystalline structure were selected by the organic solvent. The obtained organic soluble GQDs (O-GQDs) showed a significant difference in structure and composition compared with ordinary aqueous soluble GQDs, thus leading to a series of novel properties. Furthermore, O-GQDs were applied as electron-acceptors in a poly(3-hexylthiophene) (P3HT)-based organic photovoltaic device. The performance highlights that O-GQD has potential to be a novel electron-acceptor material due to the sp(2) hybridized carbon atom dominant structure and good solubility in organic solvents.

Fast P3HT Exciton Dissociation and Absorption Enhancement of Organic Solar Cells by PEG-Functionalized Graphene Quantum Dots

“…For PEG‐functionalized GQDs, we determined the LUMO to be ~3.3 eV by cyclic voltammetry (Figure S2, Supporting Information). This level is in line with many previously reported values for GQDs, which range from 3.2 to 3.6 eV, and it sits between the LUMO levels of P3HT and PCBM. The graphene‐P3HT interface is known to promote fast electron exchange, so the rapid transfer of bound electrons from the LUMO of P3HT to the GQD is likely the mechanism by which the exciton dissociates.…”

A Novel Route to High-Quality Graphene Quantum Dots by Hydrogen-Assisted Pyrolysis of Silicon Carbide

“…Both values indicate a relatively high crystallinity considering that a large number of disordered edges exist on the GQDs [28]. It is notable that such a high 2D band, as seen in this study, has rarely been reported for previously synthesized GQDs [16,35,36]. The AFM image shows that the average thickness of the GQDs is ~0.972 nm, as shown in Figure 3b, indicating that the GQDs synthesized have few layers.…”

Photobleaching and stabilization of carbon nanodots produced by solvothermal synthesis

“…[11][12][13] Studies on the photostability of CDs itself, however, are very limited. Zhao et al demonstrated that the CDs produced by electro-oxidation of graphite showed no appreciable changes in photoluminescence intensity even after continuous exposure to white light of a 8.3 W Xe lamp.…”

“…The CDs synthesized from ''bottom-up'' are always quasi-spherical without a crystal lattice. These CDs consist of aggregated or cross-linked structures from monomers or linear polymers formed using solvothermal, [15][16][17][18][19][20][21][22] microwave, 11,23,24 or calcination 25 methods.…”