Design of A-D-A-Type Organic Third-Order Nonlinear Optical Materials Based on Benzodithiophene: A DFT Study
Pingping Gong,
Lili An,
Junfeng Tong,
Xinpeng Liu,
Zezhou Liang,
Jianfeng Li
Affiliations
Pingping Gong
Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
Lili An
Key Laboratory of Optoelectronic Technology and Intelligent Control of Ministry Education, Lanzhou Jiaotong University, Lanzhou 730070, China
Junfeng Tong
Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
Xinpeng Liu
Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
Zezhou Liang
Key Laboratory of Physical Electronics and Devices of the Ministry of Education & Shaanxi Key Lab of Photonic Technique for Information, School of Electronic Science and Engineering, Faculty of Electronic and Information Engineering, Xi’an Jiaotong University, Xi’an 710049, China
Jianfeng Li
Gansu Provincial Engineering Research Center for Organic Semiconductor Materials and Application Technology, School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
The acceptor-donor-acceptor (A-D-A) type conjugated organic molecule has been widely applied in the organic optoelectronics field. A total of Nine compounds (1–9) were designed under the A-D-A framework, with the electron donor benzodithiophene as the core and dicyanomethylene as the acceptor moiety, modifying the benzodithiophene with the phenyl, naphthyl, and difluorinated phenyl groups. The conjugation length can be changed by introducing a thiophene π-conjugated bridge. The geometric structures, electronic structure, excited state properties, aromaticity, and the static- and frequency-dependent second hyperpolarizabilities were investigated by employing high-precision density functional theory (DFT) calculations with an aug-cc-pVDZ basis set. As a result, the three compounds with the longest conjugation length exhibit a smaller energy gap (Egap), larger UV-vis absorption coefficient, and response range, which are the three strongest third-order nonlinear optical (NLO) response properties in this work. This work systematically explored the connection between molecular structure and NLO response, which provides a rational design strategy for high-performance organic NLO materials.
