Developing Novel Lattice Mapping for Accurate and Efficient Charge Transport Modeling from Atomistic Morphology.

Abstract

This study focuses on numerical methods to compute charge carrier mobility in disordered materials, such as organic light-emitting diodes (OLEDs), based solely on molecular structures. The approach involves developing an ab initio method for calculating charge carrier mobility in organic materials using kinetic Monte Carlo (KMC) simulations. These simulations utilize Marcus rates derived from precise calculations of transfer integrals and site energies specific to the material's morphology. Going beyond the current approach to tackle a multicharge model system presents computational challenges, particularly in calculating site energies. To address this issue, a novel lattice mapping method was developed to efficiently determine transfer integrals and site energies from realistic morphologies while keeping computational costs manageable. Validation of the method was conducted by comparing mobility values computed using the KMC method with experimental data, showing a good agreement. Further insights into charge transport dynamics were gained through the analysis of charge carrier behavior using residence time calculations. Additionally, the model's applicability to multicharge systems was demonstrated by simulating exciton formation. In conclusion, the model has the potential to effectively and accurately simulate charge carrier trajectories in multicharge, multilayer models with minimal loss of information from realistic morphology, making it a valuable tool for designing and optimizing organic electronic devices.