Physikalisches Institut, Universität Würzburg, 97074 Würzburg, Germany.
Institut für Physikalische und Theoretische Chemie, Universität Würzburg, 97074 Würzburg, Germany.
J Chem Phys. 2014 Jan 14;140(2):024503. doi: 10.1063/1.4858464.
Due to its importance for the function of organic optoelectronic devices, accurate simulations of the singlet exciton diffusion are crucial to predict the performance of new materials. We present a protocol which allows for the efficient directional analysis of exciton transport with high-level ab initio methods. It is based on an alternative to the frequently employed rate equation since the latter was found to be erroneous in some cases. The new approach can be used in combination with the master equation which is considerably faster than the corresponding Monte Carlo approach. The long-range character of the singlet exciton coupling is taken into account by an extrapolation scheme. The approach is applied to singlet exciton diffusion in those substances where these quantities are experimentally best established: naphthalene and anthracene. The high quality of the crystals, furthermore, diminish uncertainties arising from the geometrical structures used in the computations. For those systems, our new approach provides exciton diffusion lengths L for naphthalene and anthracene crystals which show an excellent agreement with their experimental counterparts. For anthracene, for example, the computed L value in a direction is computed to 58 nm while the experimental value is 60 ± 10 nm.
由于其对有机光电设备功能的重要性，准确模拟单重激子扩散对于预测新材料的性能至关重要。我们提出了一种协议，该协议允许使用高级从头算方法有效地进行激子输运的定向分析。它基于替代经常使用的速率方程的方法，因为后者在某些情况下被发现是错误的。新方法可以与主方程结合使用，主方程比相应的蒙特卡罗方法快得多。通过外推方案考虑了单重激子耦合的长程特征。该方法应用于那些实验上最好确定这些量的物质中单重激子扩散：萘和蒽。此外，高质量的晶体减少了计算中使用的几何结构引起的不确定性。对于这些系统，我们的新方法提供了萘和蒽晶体的激子扩散长度 L，它们与实验值非常吻合。例如，对于蒽，在一个方向上计算的 L 值为 58nm，而实验值为 60±10nm。
