Structural Correlations and Percolation in Twisted Perylene Diimides Using a Simple Anisotropic Coarse-Grained Model

Area of Science:

• Materials Science
• Computational Chemistry
• Organic Electronics

Background:

• Large, twisted, and fused conjugated molecular architectures are increasingly studied in organic semiconductors.
• Conventional simulation methods struggle with these complex structures due to computational inefficiency (atomistic) or lack of detail (isotropic coarse-grained models).

Purpose of the Study:

• To develop a computationally efficient coarse-grained model that explicitly accounts for the anisotropy of large conjugated molecular architectures.
• To enable analysis of π-stacking and electronic structure in these systems at a coarse-grained resolution.

Main Methods:

• Development of a simple coarse-grained model incorporating molecular anisotropy.
• Preservation of relative orientations of conjugated rings and inter-ring dihedrals.
• Application of the model to perylene diimide (PDI)-based organic semiconductors.

Main Results:

• The model successfully analyzes π-stacking and electronic structure at coarse-grained resolution.
• Twisted and nonplanar molecular architectures promote amorphous morphologies while maintaining local π-stacking.
• Graph theoretical network analysis showed twisted molecules form 3D charge transport pathways, while planar molecules exhibit 1D connectivity.

Conclusions:

• The developed coarse-grained model offers an efficient approach to study complex organic semiconductor architectures.
• Molecular twist and nonplanarity are crucial for achieving desirable charge transport properties in bulk organic semiconductors.