| Summary: | 碩士 === 國立交通大學 === 材料科學與工程系 === 90 === This report is to synthesize and investigate novel photoluminent materials containing five conjugated-rings with alkoxy-substituted side groups. These compounds and analogous polymers containing conjugated and flexible parts are synthesized by Witting-Hohner reaction . These model compounds having five conjugated-rings are compared with the derivative polymers . By modification of the side chains and end groups of the conjugated molecules, we are able to characterize their mesogenic behavior by DSC and POM. The measurements reveal that appropriate lengths of the side chains and end groups result in better liquid crystallinity (the nematic phase); however, the range of the mesogenic phase is reduced at longer lengthsof above chains. The optical and electric properties of the compounds are determined by UV-vis, photoluminescent (PL) and electroluminescent (EL). These measurements reveal that the tuning of side chains and end groups would not affect their fluorescence properties significantly. To conclude this report, we have developed novel fluorescent conjugated compounds possessing mesogenic properties, which can generate polarized light in the aligned nematic phase by using parallel alignment cells. We have succeed in producing polarized photoluminescent cells by application of the liquid crystalline phase.
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