Complexes of C60 with cyclic oligothiophenes: a theoretical study

Area of Science:

• Computational chemistry
• Materials science
• Organic electronics

Background:

• Fullerene (C60) and oligothiophenes are key components in organic electronic materials.
• Understanding their complexation is crucial for optimizing material properties.

Purpose of the Study:

• To model and analyze the binding energies and electronic properties of C60-oligothiophene complexes.
• To investigate the influence of oligothiophene structure and charge states on complex stability and charge transfer.

Main Methods:

• Density functional theory calculations using the M05-2X/6-311G**//M05-2X/6-31G* level of theory.
• Basis set superposition error (BSSE) correction for binding energies.
• Analysis of charge distribution in neutral, oxidized, and reduced states.

Main Results:

• Binding energies for neutral C60-oligothiophene complexes range from 5 to 12 kcal/mol.
• Inclusion complexes of C60 with cyclooligothiophenes (8 repeating units) are the most stable.
• Weak ground-state charge transfer occurs, while complete charge transfer is observed in the excited state.
• Oxidation/reduction affects binding energies, concentrating charge on oligothiophene (cation) or C60 (anion).

Conclusions:

• Planar oligothiophene conformation and weak binding favor photoinduced charge-carrier formation.
• These findings provide insights into designing efficient organic electronic materials based on C60-oligothiophene systems.