Besalú-Sala Pau, Voityuk Alexander A, Luis Josep M, Solà Miquel
Institut de Química Computacional i Catàlisi and Departament de Química, Universitat de Girona, C/M. Aurèlia Capmany, 69, 17003, Girona, Catalonia, Spain.
Phys Chem Chem Phys. 2021 Mar 11;23(9):5376-5384. doi: 10.1039/d0cp06510b.
The shift towards renewable energy is one of the main challenges of this generation. Dye-sensitized solar cells (DSSCs), based on donor-acceptor architectures, can help in this transition as they present excellent photovoltaic efficiencies yet cheap and simple manufacturing. For molecular heterojunction DSSCs, donor-acceptor pairs are linked in a covalent manner, which facilitates their tailoring and rational design. Nevertheless, reliable computational characterization of charge transfer rate constants (kCT) is needed to speed this development process up. In this context, the performance of time-dependent density functional theory for the calculation of kCT values in donor-acceptor fullerene-based dyads has not been benchmarked yet. Herein, we present a detailed analysis on the performance of seven well-known density functional approximations (DFAs) for this type of system, focusing on several parameters such as the reorganization energies (λ), electronic couplings (VDA), and Gibbs energies (ΔG0CT), as well as the final rate constants. The amount of exact exchange at short range (SR) and long range (LR) electron-electron distances (and the transition from the SR to LR) turned out to be key for the success of the prediction. The tuning of these parameters improves significantly the performance of current DFAs.
向可再生能源的转变是这一代人面临的主要挑战之一。基于供体-受体结构的染料敏化太阳能电池（DSSC）有助于实现这一转变，因为它们具有出色的光伏效率，而且制造便宜且简单。对于分子异质结DSSC，供体-受体对以共价方式连接，这便于它们的定制和合理设计。然而，需要对电荷转移速率常数（kCT）进行可靠的计算表征，以加快这一开发过程。在此背景下，用于计算基于供体-受体富勒烯二元体系中kCT值的含时密度泛函理论的性能尚未得到评估。在此，我们对这类体系的七种著名密度泛函近似（DFA）的性能进行了详细分析，重点关注几个参数，如重组能（λ）、电子耦合（VDA）和吉布斯自由能（ΔG0CT），以及最终的速率常数。事实证明，短程（SR）和长程（LR）电子-电子距离处的精确交换量（以及从SR到LR的转变）是预测成功的关键。对这些参数的调整显著提高了当前DFA的性能。
