Donor and acceptor levels of organic photovoltaic compounds from first principles

TL;DR

This paper demonstrates that orbital-dependent density-functional theory based on Koopmans' condition can accurately predict donor and acceptor levels in organic photovoltaic compounds, offering a computationally efficient alternative to more costly methods.

Contribution

It introduces a practical first-principles approach using Koopmans' condition to accurately determine energy levels in organic photovoltaic materials.

Findings

Orbital-dependent DFT accurately predicts donor and acceptor levels within 0.1 eV of experiments.

The method offers similar accuracy to many-body perturbation theory but at lower computational cost.

Applicable to a wide range of organic molecules, clusters, and oligomers.

Abstract

Accurate and efficient approaches to predict the optical properties of organic semiconducting compounds could accelerate the search for efficient organic photovoltaic materials. Nevertheless, predicting the optical properties of organic semiconductors has been plagued by the inaccuracy or computational cost of conventional first-principles calculations. In this work, we demonstrate that orbital-dependent density-functional theory based upon Koopmans' condition [Phys. Rev. B 82, 115121 (2010)] is apt at describing donor and acceptor levels for a wide variety of organic molecules, clusters, and oligomers within a few tenths of an electron-volt relative to experiment, which is comparable to the predictive performance of many-body perturbation theory methods at a fraction of the computational cost.