Theory-Guided Design and Synthesis of Multichromophore Dendrimers: An Analysis of the Electro-optic Effect

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• 作者：Philip A. Sullivan ; Harrison Rommel ; Yi Liao ; Benjamin C. Olbricht ; Andrew J. P. Akelaitis ; Kimberly A. Firestone ; Jae-Wook Kang ; Jingdong Luo ; Joshua A. Davies ; Dong Hoon Choi ; Bruce E. Eichinger ; Ph
• 刊名：Journal of the American Chemical Society
• 出版年：2007
• 出版时间：June 20, 2007
• 年：2007
• 卷：129
• 期：24
• 页码：7523 - 7530
• 全文大小：312K
• 年卷期：v.129,no.24(June 20, 2007)
• ISSN：1520-5126

文摘

Extensive experimental and theoretical study suggests that interchromophore electrostaticinteractions are among the most severe impediments to the induction and stability of large electro-opticcoefficients in electric-field-poled organic materials. In this report, multichromophore-containing dendriticmaterials have been investigated as a means to minimize unwanted attenuation of nonlinear optical (electro-optic) activity at high chromophore loading. The dendritic molecular architectures employed were designedto provide optimized molecular scaffolding for electric-field-induced molecular reorientation. Designparameters were based upon past experimental results in conjunction with statistical and quantummechanical modeling. The electro-optic behavior of these materials was evaluated through experimentaland theoretical analysis. Experimental data collected from the dendrimer structures depict a reasonablylinear relationship between chromophore number density (N) and electro-optic activity (r₃₃) demonstratinga deviation from the dipolar frustration that typically limits r₃₃ in conventional chromophore/polymer compositematerials. The observed linear dependence holds at higher chromophore densities than those that havebeen found to be practical in systems of organic NLO chromophores dispersed in polymer hosts. Theoreticalanalysis of these results using Monte Carlo modeling reproduces the experimentally observed trendsconfirming linear dependence of electro-optic activity on N in the dendrimer materials. These results providenew insight into the ordering behavior of EO dendrimers and demonstrate that the frequently observedasymptotic dependence of electro-optic activity on chromophore number density may be overcome throughrational design.