Diffusion of aggregated fullerenes in solution

Abstract

The diffusion of fullerenes in solution is studied taking into account the recently established formation of clusters containing numbers of aggregated fullerence molecules. Based on a droplet model of a cluster, the distribution function of fullerence clusters by size is obtained for various concentrations of solution. It is shown that dissolved fullerene is present mainly in the form of clusters at saturation conditions, but the contribution of clusters diminishes as the concentration decreases. Since the diffusion mobility of clusters is much less than that of molecules, it leads to the dependence of an effective diffusion coefficient on concentration, which is computed for the case of fullerence C60. The feasibility of the use of this dependence as a basis for a diffusion method of the separation and enrichment of the fullerene extract with a small addition of higher fullerenes is analyzed. Possible schemes for enrichment are discussed.

Aggregation of Fullerene, C60, in Benzonitrile

“…The differences between the C 60 and C 70 in aggregation behaviour could be useful for their separation and enrichment. 37…”

“…The highly symmetric structure of C 60 might be suitable for the packing required for the aggregation but not for asymmetric C 70 . The differences between the C 60 and C 70 in aggregation behaviour could be useful for their separation and enrichment …”

Fullerenes in solutions

“…Let us analyze the one-dimensional nonstationary problem on the diffusion of fullerenes in a solution with allowance made for the concentration dependence of the diffusion coefficient as determined above [44]. We shall assume that the source of fullerenes is provided by a plane layer of a solid material constituting the mixture of fullerenes of two sorts, in which fullerene molecules of a certain sort predominate, whereas the molecules of the other sort make up only a minor impurity.…”

Fullerenes in Aromatic Solvents: Correlation between Solvation-Shell Structure, Solvate Formation, and Solubility

“…Fullerene, C 60 , and its derivatives have been the subject of study for a vast array of biological and electronic applications ranging from anticancer treatments , and liver-protective antioxidants to liquid-crystal materials and organic photovoltaic (OPV) devices. − The most ubiquitous fullerene derivative as an OPV material is phenyl-C 61 -butyric acid methyl ester (PCBM), which is considered the benchmark for electron-acceptor materials in bulk-heterojunction (BHJ) OPVs. − The primary applications of fullerenes necessitate solution-based processing; however, fullerene exhibits unusual solubility behavior because of its unique chemical structure. − In OPVs, for example, the solubility of the fullerene acceptor material has a direct impact on OPV device performance as a result of fullerene aggregation behavior during deposition of the BHJ active layer. − Thus, a large number of experimental, ,− theoretical, , and computational − studies into fullerene solvation behavior have been performed. Moreover, a variety of theoretical models have been employed to predict fullerene solubility based on solvent properties. ,− Although these studies have provided valuable insights into the properties of solvents that tend to produce high C 60 solubility limits, it is difficult to directly relate these properties to the interactions occurring during solvation.…”