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

Area of Science:

• Physical Chemistry
• Materials Science
• Computational Chemistry

Background:

• Fullerene derivatives like C60 and PCBM are crucial in organic electronics.
• Their solubility in organic solvents is a key factor for processing and device performance.
• Understanding solvation dynamics is essential for predicting and enhancing solubility.

Purpose of the Study:

• To investigate the dynamic structure of solvation shells around C60 and PCBM in aromatic solvents.
• To develop a novel method for visualizing and quantifying solvent molecule orientations within solvation shells.
• To establish a correlation between solvation shell structure and the solubility limits of C60 and PCBM.

Main Methods:

• All-atom molecular dynamics (MD) simulations were performed.
• Nine aromatic solvents were used to study C60 and PCBM solvation.
• A new visualization and quantification technique for solvent orientation distribution was developed.

Main Results:

• A strong positive correlation was identified between the regularity of solvent orientations and experimental solubility.
• The study successfully predicted a solubility of 36 g/L for PCBM in 1,2,4-trimethylbenzene.
• Solvation shell structure was found to depend on the geometric shape of the solvent molecules.

Conclusions:

• The relationship between solvation shell structure and solubility offers detailed insights into fullerene solvate formation.
• Tailoring solvent molecular structure based on geometric shape can enhance control over fullerene solution-phase behavior.
• This approach may reduce reliance on harmful halogenated solvents and additives in fullerene processing.