Redox and Photoisomerization Switching the Second-Order Nonlinear Optical Properties of a Tetrathiafulvalene Derivative Across Six States: A DFT Study

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• 作者：Chun-Guang Liu ; Zhong-Min Su ; Xiao-Hui Guan ; Shabbir Muhammad
• 刊名：Journal of Physical Chemistry C
• 出版年：2011
• 出版时间：December 8, 2011
• 年：2011
• 卷：115
• 期：48
• 页码：23946-23954
• 全文大小：1060K
• 年卷期：v.115,no.48(December 8, 2011)
• ISSN：1932-7455

文摘

The switching of second-order nonlinear optical (NLO) properties for a tetrathiafulvalene (TTF) derivative across the six stable states has been studied by using the density functional theory (DFT) calculations. The redox-active TTF unit and a photoisomerized chromophore 1,2-dithienylperfluorocyclopentene (DTE) have been implemented to switch the second-order NLO responses. Our DFT calculations with three functionals demonstrate that introduction of the DTE moiety into the 蟺-conjugated bridge can significantly enhance the second-order NLO response relevant to the donor/acceptor end in this work. Our DFT calculations illustrate that photoisomerization bring forth a large change in the geometry of the series of compounds. The closed-ring form possesses a good 蟺-conjugation relative to the open-ring form and thus a large second-order NLO response. The electronic structure analysis shows that the TTF unit will perform as an oxidation center in the one- and two-electron-oxidation processes. The one- and two-electron-oxidized species have better planar structures of TTF unit than its neutral compound, which ultimately leads to the low excited energy and enhances the static first hyperpolarizability. Our present DFT calculations using three functionals show that the TTF derivative 4 can switch the second-order NLO properties across six stable states, which is a rare example in previously reported second-order NLO switches.