Delocalised kinetic Monte Carlo for simulating delocalisation-enhanced charge and exciton transport in disordered materials
| Autor: | Thijs J.A.M. Smolders, Samantha N. Hood, David Blyth, Ivan Kassal, Daniel Balzer |
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| Rok vydání: | 2020 |
| Předmět: |
Physics
Chemical Physics (physics.chem-ph) Condensed Matter - Materials Science Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Condensed Matter::Other Exciton Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Charge (physics) General Chemistry Thermal conduction Condensed Matter::Disordered Systems and Neural Networks Electronic states Organic semiconductor Chemistry Physics - Chemical Physics Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Kinetic Monte Carlo Wave function Quantum |
| Zdroj: | Chemical Science |
| DOI: | 10.48550/arxiv.2007.13986 |
| Popis: | Charge transport is well understood in both highly ordered materials (band conduction) or highly disordered ones (hopping conduction). In moderately disordered materials—including many organic semiconductors—the approximations valid in either extreme break down, making it difficult to accurately model the conduction. In particular, describing wavefunction delocalisation requires a quantum treatment, which is difficult in disordered materials that lack periodicity. Here, we present the first three-dimensional model of partially delocalised charge and exciton transport in materials in the intermediate disorder regime. Our approach is based on polaron-transformed Redfield theory, but overcomes several computational roadblocks by mapping the quantum-mechanical techniques onto kinetic Monte Carlo. Our theory, delocalised kinetic Monte Carlo (dKMC), shows that the fundamental physics of transport in moderately disordered materials is that of charges hopping between partially delocalised electronic states. Our results reveal why standard kinetic Monte Carlo can dramatically underestimate mobilities even in disordered organic semiconductors, where even a little delocalisation can substantially enhance mobilities, as well as showing that three-dimensional calculations capture important delocalisation effects neglected in lower-dimensional approximations. The first three-dimensional model of transport in moderately disordered materials shows that a little delocalisation can dramatically enhance mobilities. |
| Databáze: | OpenAIRE |
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