Nanostructuration of Phenylenevinylenediimide-Bridged Silsesquioxane: From Electroluminescent Molecular J-Aggregates to Photoresponsive Polymeric H-Aggregates
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- 作者：Olivier J. Dautel ; Guillaume Wantz ; Robert Almairac ; David Flot ; Lionel Hirsch ; Jean-Pierre Lere-Porte ; Jean-Paul Parneix ; Franç ; oise Serein-Spirau ; Laurence Vignau ; and Joë ; l J. E. Moreau
- 刊名：Journal of the American Chemical Society
- 出版年：2006
- 出版时间：April 12, 2006
- 年：2006
- 卷：128
- 期：14
- 页码：4892 - 4901
- 全文大小：441K
- 年卷期：v.128,no.14(April 12, 2006)
- ISSN：1520-5126
文摘
A new approach to control molecular aggregation of 
-conjugated chromophores in the solidstate has been investigated. Our strategy was to use a modifiable bulky fragment which should induce aJ-aggregation and offer the possibility to reach an H-aggregation upon its chemical modification by lateralslip of -conjugated molecules. The chosen fragment for that purpose was the hydrolyzable triethoxysilanefunction (Si(OEt)3). Our objective was to design and synthesize electroluminescent or solar cell hybridorganic-inorganic materials by the sol-gel process applied to a bifunctionalized silane. With this intention,the synthesis of the sol-gel processable phenylenevinylenediimide silsesquioxane 6 was accomplishedand the study of spin-coated thin films of the pure silane precursor subjected or not to the sol-gel processhas been carried out. Optical properties of 6 are consistent with the formation of J-aggregates in the solidstate due to the steric hindrance introduced by the triethoxysilane units. Conversely, the spectroscopicbehavior observed for the hybrid film 6F is attributed to an H-aggregation corresponding to a "card pack"orientation of the distyrylbenzeneimide chromophores in the compressed silicate network. Morevover, 6and 6F also exhibited different electronic behaviors: light-emitting diodes exhibited high brightness withthe native precursor 6 and almost no light output with the sol-gel processed silsesquioxane 6F. Photovoltaiccells showed the opposite behavior with low photocurrent generation in the precursor case and higherphotocurrents with the sol-gel processed layers. These results provide a deeper understanding of thepresent self-assembly process that is strongly governed by the molecular packing of the oligosiloxaneprecursor.
-conjugated chromophores in the solidstate has been investigated. Our strategy was to use a modifiable bulky fragment which should induce aJ-aggregation and offer the possibility to reach an H-aggregation upon its chemical modification by lateralslip of -conjugated molecules. The chosen fragment for that purpose was the hydrolyzable triethoxysilanefunction (Si(OEt)3). Our objective was to design and synthesize electroluminescent or solar cell hybridorganic-inorganic materials by the sol-gel process applied to a bifunctionalized silane. With this intention,the synthesis of the sol-gel processable phenylenevinylenediimide silsesquioxane 6 was accomplishedand the study of spin-coated thin films of the pure silane precursor subjected or not to the sol-gel processhas been carried out. Optical properties of 6 are consistent with the formation of J-aggregates in the solidstate due to the steric hindrance introduced by the triethoxysilane units. Conversely, the spectroscopicbehavior observed for the hybrid film 6F is attributed to an H-aggregation corresponding to a "card pack"orientation of the distyrylbenzeneimide chromophores in the compressed silicate network. Morevover, 6and 6F also exhibited different electronic behaviors: light-emitting diodes exhibited high brightness withthe native precursor 6 and almost no light output with the sol-gel processed silsesquioxane 6F. Photovoltaiccells showed the opposite behavior with low photocurrent generation in the precursor case and higherphotocurrents with the sol-gel processed layers. These results provide a deeper understanding of thepresent self-assembly process that is strongly governed by the molecular packing of the oligosiloxaneprecursor.