Impact of the dielectric constant on the first hyperpolarizabilities and the Singlet−Triplet gap in T- and V-Shaped donor-acceptor-donor molecules

Autor: Haiming Xie, Hong-Qiang Wang, Jin-Ting Ye, Li Wang, Yong-Qing Qiu
Rok vydání: 2019
Předmět:
Zdroj: Organic Electronics. 70:193-204
ISSN: 1566-1199
DOI: 10.1016/j.orgel.2019.04.021
Popis: Interesting T- and V-shaped molecules consisting of donor (D) - acceptor (A) - donor (D) involving a new acceptor core of pyridoquinoxaline has been synthesized, and has attracted intensive research interest due to its intramolecular charge transfer (ICT) -driven thermally activated delayed fluorescence (TADF) and nonlinear optical effects (NLO) characteristics. In the present work, the structure and electronic properties of T- and V-shaped molecules under the gas phase and the solid-state environment are explored based on the combination of a nonempirical, optimally tuned range-separated hybrid functional with the polarizable continuum model (PCM): (1) The singlet-triplet gap (ΔEST) of all studied molecules in gas phase are reduced by an order of magnitude the solid-state environment, indicating they are potentially efficient TADF materials. (2) The ΔEST decrease in the solid state is attributed to the simultaneous presence of dominant 1CT and 3CT excited states under the solid-state polarization. (3) Compared with the T-shaped system, the V-shaped molecules can be dramatically enhanced NLO coefficient (βtot = 59.7 × 10−30 esu) in vacuum, which is due to the larger separate distributions of first hyperpolarizability density. (4) More importantly, the polarization effect effectively regulates and controls the NLO response of all studied molecules. The present work provides an effective strategy for developing the high-performance TADF and NLO materials by tuning the polarization effect and the connected style between D and A units.
Databáze: OpenAIRE
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