The Photopolymerization and Cross-Linking of Electroluminescent Liquid Crystals Containing Methacrylate and Diene Photopolymerizable End Groups for Multilayer Organic Light-Emitting Diodes

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• 作者：Adam E. A. Contoret ; Simon R. Farrar ; Mary O'Neill ; J. Edward Nicholls ; Gary James Richards ; Stephen Malcom Kelly ; and Alan William Hall
• 刊名：Chemistry of Materials
• 出版年：2002
• 出版时间：April 2002
• 年：2002
• 卷：14
• 期：4
• 页码：1477 - 1487
• 全文大小：139K
• 年卷期：v.14,no.4(April 2002)
• ISSN：1520-5002

文摘

Light-emitting liquid crystals incorporating two photopolymerizable end groups have beensynthesized for implementation in multilayer organic electroluminescent devices. Series ofdiene as well as diallylamine and methacrylate moieties are used as the photoreactive groupsattached via spacers to both ends of a fluorene-based chromophore. Nematic glasses areformed upon cooling from the liquid crystalline phase. Ultraviolet radiation at roomtemperature is used to photopolymerize and cross-link the reactive units, resulting in theformation of insoluble nematic polymer networks. The quantum efficiency of photoluminescence from the fluorene-based chromophore is increased by cross-linking of the diene reactiveend groups. Photopolymerization occurs more rapidly with methacrylate end groups, butthe chromophore is somewhat degraded by the incident radiation. In materials incorporatingthe photopolymerizable 1,4-pentadien-3-yl group, the formation of the polymer networkenhances the electroluminescence. An electron-transporting polymer containing an oxaziaolering is deposited on top of the insoluble network. Electroluminescence is obtained with anunchanged spectrum.