# Exciton Dissociation and Charge Separation at Donor-Acceptor Interfaces from Quantum-Classical Dynamics Simulations

## TL;DR

This paper uses quantum-classical simulations to study exciton dissociation and charge separation at donor-acceptor interfaces in organic photovoltaics, evaluating the accuracy and efficiency of the FBTS method across models.

## Contribution

It introduces and benchmarks the FBTS quantum-classical dynamics method for simulating exciton dissociation at donor-acceptor interfaces.

## Key findings

- FBTS provides a reasonable accuracy-cost balance.
- Dimensionality influences initial charge separation dynamics.
- Benchmark results highlight strengths and limitations of FBTS.

## Abstract

In organic photovoltaic (OPV) systems, exciton dissociation and ultrafast charge separation at donor-acceptor heterojunctions both play a key role in controlling the efficiency of the conversion of excitation energy into free charge carriers. In this work, nonadiabatic dynamics simulations based on the quantum-classical Liouville equation, are employed to study the real-time dynamics of exciton dissociation and charge separation at a model donor-acceptor interface. Benchmark comparisons for a variety of low dimensional donor-acceptor chain models are performed to assess the accuracy of the quantum classical dynamics technique referred to as the forward-backward trajectory solution (FBTS). Although not always quantitative, the FBTS approach offers a reasonable balance between accuracy and computational cost. The short-time dynamics of exciton dissociation in related higher-dimensional lattice models for the interface are also investigated to assess the effect of the dimensionality on the first steps in the mechanism of charge carrier generation.