Photoinduced electron transfer in [10]CPP⊃C60 oligomers with stable and well-defined supramolecular structures

Area of Science:

• Materials Science
• Organic Electronics
• Computational Chemistry

Background:

• Cyclic π-conjugated polymers offer unique electronic properties for organic photovoltaics (OPVs).
• Cycloparaphenylene (CPP) macrocycles integrated into polymer backbones present a novel class of materials.
• Understanding charge transfer dynamics in these systems is crucial for OPV device efficiency.

Purpose of the Study:

• To theoretically investigate the ground and excited state properties of novel CPP-based polymers.
• To examine the influence of fullerene inclusion on polymer chain structures and electronic behavior.
• To evaluate the efficiency and timescale of photoinduced electron transfer in polymer-fullerene systems.

Main Methods:

• Density Functional Theory (DFT) calculations for electronic structure.
• Molecular Dynamics (MD) simulations to explore structural properties and stability.
• Analysis of charge transfer rates (electron and hole transfer, recombination).

Main Results:

• Oligomers with π-extended CPPs ([10]CPP_Fused⊃C60)24 and ([10]CPP_Fused⊃C60)32 form stable, helix-like structures.
• Photoinduced electron transfer from the CPP-based polymer to C60 fullerene is thermodynamically favorable.
• Electron and hole transfer occur on a nanosecond timescale, significantly faster than charge recombination.

Conclusions:

• CPP-based polymers form stable helical structures when complexed with fullerenes.
• Efficient and rapid photoinduced electron transfer from polymer to fullerene facilitates charge separation.
• These findings highlight the potential of cyclic π-conjugated materials for high-performance organic photovoltaics.