Electronic and photophysical properties of selected organic boron-containing molecules: Insight into effects of heteroatom substitution and aggregation |
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Authors: | Lin Zhang Zexing Cao |
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Institution: | State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Provincial Key Laboratory of Theoretical and Computational Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China |
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Abstract: | The density functional theory (DFT) and time-dependent DFT methods were used to investigate the electronic and optoelectronic properties of several main group atom-doped polycyclic aromatic hydrocarbons, such as oxygen-substituted PHO1 and PHO2, and sulfur-substituted PHS1 and PHS2. The ground-state structures of these molecules generally have an open-shell singlet configuration with a certain diradical character. In comparison with PHO1 and PHO2, PHS1 and PHS2 own larger diradical character indices due to their increased anti-aromaticity. Although the substitution of sulfur for the peripheral oxygen has a significant effect on the molecular geometry, the adiabatic excitation energy levels of the corresponding low-lying excited states of these molecules are less changed. Calculations reveal that here the intersystem crossing (ISC) and reverse intersystem crossing processes in CH2Cl2 mainly occur between the S1 and T2 states, and the cis molecules PHO2 and PHS2 have better charge transportation performance. Furthermore, the electronic and photophysical properties of these B-containing molecules are predicted to be tuned by the peripheral atom substitution and the structural and aggregation changes. |
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Keywords: | boron-containing molecules DFT and TD-DFT calculations excited states heteroatom substitution photophysical properties |
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