Implicit and explicit host effects on excitons in pentacene derivatives
Implicit and explicit host effects on excitons in pentacene derivatives
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DOI：
10.1063/1.5017285
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发表时间：
2018-03-14
影响因子：
4.4
通讯作者：
Haynes, P. D.
中科院分区：
文献类型：
--
作者：
Charlton, R. J.;Fogarty, R. M.;Haynes, P. D.
采用基态密度泛函理论（DFT）、含时密度泛函理论（TDFT）和Delta自洽场方法，对并五苯及其氮基衍生物的激发态性质进行了从头算研究.我们观察到一个显着的溶致变色红移的激发能的最低单重态（S-1）的并五苯从列入对三联苯主机相比，真空;对于一个明确的主机组成的六个最近的邻居对三联苯，我们得到一个红移为65毫电子伏，而导体样的极化连续模型（CPCM）产生78毫电子伏的红移。并五苯和它的四个氮基类似物，1，8-，2，9-，5，12-和6，13-diazapentacene的激子性质之间的比较被发现是最明显的，由于在基态电子结构的局部扭曲。我们观察到，一个CPCM是不足以充分了解主机的影响，由于存在一个温和的电荷转移（CT）之间的耦合的发色团和相邻的p-三联苯，这一现象只能被捕获使用一个明确的模型。这种CT相互作用的强度随着氮更靠近并五苯的中心并苯环而增加。由AIP出版社出版。
An ab initio study of the effects of implicit and explicit hosts on the excited state properties of pentacene and its nitrogen-based derivatives has been performed using ground state density functional theory (DFT), time-dependent DFT, and Delta SCF. We observe a significant solvatochromic redshift in the excitation energy of the lowest singlet state (S-1) of pentacene from inclusion in a p-terphenyl host compared to vacuum; for an explicit host consisting of six nearest neighbour p-terphenyls, we obtain a redshift of 65 meV while a conductor-like polarisable continuum model (CPCM) yields a 78 meV redshift. Comparison is made between the excitonic properties of pentacene and four of its nitrogen-based analogs, 1,8-, 2,9-, 5,12-, and 6,13-diazapentacene with the latter found to be the most distinct due to local distortions in the ground state electronic structure. We observe that a CPCM is insufficient to fully understand the impact of the host due to the presence of a mild charge-transfer (CT) coupling between the chromophore and neighbouring p-terphenyls, a phenomenon which can only be captured using an explicit model. The strength of this CT interaction increases as the nitrogens are brought closer to the central acene ring of pentacene. Published by AIP Publishing.