Triplet Exciton Transfers and Triplet?Triplet Annihilation in Anthracene Derivatives via Direct versus Superexchange Pathways Governed by Molecular Packing
Triplet Exciton Transfers and Triplet?Triplet Annihilation in Anthracene Derivatives via Direct versus Superexchange Pathways Governed by Molecular Packing
复制标题
蒽衍生物中的三重态激子转移和三重态？三重态湮灭通过分子堆积控制的直接与超交换途径
DOI：
10.1021/acs.jpca.0c06835
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Tamura Hiroyuki
中科院分区：
文献类型：
--
作者：
Mitsuhashi Koji;Tamura Hiroyuki;Saito Keisuke;Ishikita Hiroshi;Tamura Hiroyuki
从理论上分析了9，10-双(三异丙基硅乙炔基)蒽(TIPS-ANTP)和1，2，3，4-tetrafluoro-5，8-bis(trimethylsilylethynyl)anthracene(F4-TMS-ANT)中的三重态激子转移(TET)和三重态-三重态湮没(TTA)。结合含时密度泛函理论和多参考二阶M&Plesset方法，对TET和TTA的电子耦合进行了计算。根据考虑了分子内模的Franck-Condon因子的费米黄金法则，估算了Tet速率。用多组态含时Hartree方法对TTA进行了量子动力学计算。在界面堆积的F4-TMS-ANT中的TET比滑动堆积的TIPS-ANTP快。在蒽衍生物中，单重态激子的能量低于双三重态激子。F4-TMS-ANT由于具有较强的电子耦合作用，可通过高激发态电荷转移(CT)介导的超交换途径实现超快TTA。相反，TIPS-ANTP通过直接途径表现出低效率的TTA，具有较小的两电子耦合。界面堆积降低了到中间CT态的能隙，从而通过超交换途径促进了TET和TTA。
Triplet exciton transfer (TET) and triplet–triplet annihilations (TTAs) in anthracene derivatives, namely, one of the polymorphs of 9,10-bis(triisopropylsilylethynyl)anthracene (TIPS-ANTp) and 1,2,3,4-tetrafluoro-5,8-bis(trimethylsilylethynyl)anthracene (F4-TMS-ANT), are analyzed theoretically. The electronic couplings for TET and TTA are evaluated by means of the diabatization scheme in conjunction with the time-dependent density functional theory and the multireference second-order Møller–Plesset method. The TET rate is estimated on the basis of Fermi’s golden rule considering the Franck–Condon factor of intramolecular modes. TTA is analyzed by means of quantum dynamics calculations with the multiconfiguration time-dependent Hartree method. TET in the cofacially stacked F4-TMS-ANT is faster than that of the slip-stacked TIPS-ANTp. In the anthracene derivatives, a singlet exciton is lower in energy than a pair of triplets. F4-TMS-ANT can exhibit an ultrafast TTA via the superexchange pathway mediated by higher lying charge transfer (CT) states, owing to strong electronic couplings. In contrast, TIPS-ANTp exhibits an inefficient TTA via the direct pathway with a small two-electron coupling. The cofacial stacking decreases the energy gap to the intermediate CT states, thereby facilitating TET and TTA via the superexchange pathway.