Interlayer Force Field for the Anisotropic Interaction between Planar Organic Molecules and Two-Dimensional Hexagonal...

Area of Science:

• Materials Science
• Computational Chemistry
• Surface Science

Background:

• Simulating organic molecule adsorption on hexagonal boron nitride (hBN) is crucial for advanced materials.
• Existing models struggle with polar organic molecules due to limitations in electrostatic interaction treatment.

Purpose of the Study:

• Introduce a novel interlayer potential (ILP) for accurate simulation of polar organic molecules on hBN.
• Investigate the adsorption, diffusion, and monolayer formation of organic molecules on hBN surfaces.

Main Methods:

• Developed an all-atom electrostatic interlayer potential (ILP) incorporating short-range repulsion and long-range attraction.
• Parametrized the ILP using density functional theory data for pentacene and PTCDI.
• Performed comparative simulations of nonpolar pentacene and polar PTCDA diffusion and growth.

Main Results:

• The ILP accurately models pentacene and PTCDA, showing transferability to related molecules like PTCDA.
• Polar PTCDA exhibits stronger binding and limited diffusion via hops, while nonpolar pentacene diffuses via out-of-plane motions.
• Simulations reproduce experimentally observed morphologies: PTCDA forms a square lattice, pentacene aligns longitudinally.

Conclusions:

• The new ILP provides a computationally efficient and accurate method for simulating polar organic molecules on hBN.
• This model advances the understanding of molecular behavior, layer formation, and structural properties in organic-hBN systems.
• Enables exploration of hBN-encapsulated or -supported organic electronic devices.