Designing Efficient Azobenzene and Azothiophene Nonlinear Optical Photochromes
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- 作者：Titouan Jaunet-Lahary ; Agisilaos Chantzis ; Kathy J. Chen ; Ad猫le D. Laurent ; Denis Jacquemin
- 刊名：Journal of Physical Chemistry C
- 出版年：2014
- 出版时间：December 11, 2014
- 年：2014
- 卷：118
- 期：49
- 页码：28831-28841
- 全文大小：405K
- ISSN：1932-7455
文摘
The present contribution constitutes an extensive density functional theory (DFT) investigation of the nonlinear optical (NLO) properties of a large number of molecules belonging to the azobenzene and azothiophene families of photochromic compounds which can act as NLO switches. Toward the design of systems simultaneously presenting both large total nonlinear response values, 尾tot, and large contrast, 尾ratio, between the cis and trans isomers, we have focused not only on the monomers but also on azobenzene dimers, the latter containing two N鈺怤 bonds along the molecular backbone. After it was established that the inclusion of implicit solvation is not important in drawing qualitative conclusions on the NLO switching ability for the investigated systems, gas-phase calculations have shown that for the asymmetric push鈥損ull azobenzene and azothiophene candidates, the combination of strong donating groups such as NPh2, N(Ph-OMe)2, and N(Ph-NMe2)2 with the dicyanoethene group CH鈺怌(C鈮)2 as an acceptor delivers large 尾trans (150鈥?17 脳 10鈥?0 esu) and non-negligible 尾cis (18鈥?5 脳 10鈥?0 esu) values as well as substantial contrast, 尾ratio (3.9鈥?.7). For the investigated double azobenzenes, it is found that, with a careful choice of donor and acceptor groups, the contrast, 尾ratio, can be significantly increased compared to that of the monomers while maintaining large 尾 values that facilitate their detection with standard experimental techniques (e.g., electric-field-induced second-harmonic generation). Our results set the stage on which further theoretical and experimental studies can be based in the search for efficient and versatile NLO switches.