環雙芴基衍生物之理論計算研究

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Title:	環雙芴基衍生物之理論計算研究
Other Titles:	Theoretical study of 9,9'-spirobifluorene derivatives
Authors:	史家榮;Shih, Chia-jung
Contributors:	淡江大學化學學系碩士班王伯昌;Wang, Bo-cheng
Keywords:	環雙芴基;塞吩;聚塞吩;能隙值;HOMO;LUMO;energy gap;thiophene;Polythiophene;9,9’-Spirobifluorene
Date:	2007
Issue Date:	2010-01-11 02:44:58 (UTC+8)
Abstract:	以雙環芴基(9,9’-Spirobifluorene)為主結構，利用理論計算的方法，在不同的取代位置上，接上了不同個數的塞吩(Thiophene)，並分別做了單取代、雙取代(2,7取代和2,2’取代)和四取代，研究在不同的取代位置上，塞吩的增加會對原來的雙環芴基產生什麼影響。第一部份，利用AM1和B3LYP/6-31G求出各個結構的HOMO、LUMO、Ip和Ea值，得到了當塞吩數目增加時，-EHOMO值會逐漸下降，-ELUMO值會逐漸上升，而相對於-EHOMO和-ELUMO，Ip值也會逐漸的下降而Ea值會逐漸的上升。第二部份是利用 B3LYP/6-31G和TD B3LYP/6-31G*分別求出各結構的能隙值Eg(DFT)和Eg(TD)，並和實驗值作對照，發現當塞吩數目增加的時候，能隙值Eg(DFT)和Eg(TD)都會開始降低，和實驗值所呈現出來的數據相吻合。之後在利用上述所求得的值作出線性關係，在利用外插法，求出並預測當接上聚合物塞吩(polythiophene)的時候，HOMO、LUMO和能隙值會是多少。第三部份則是作出各結構的電子雲分布圖和利用密度態(Density of states，DOS)來相互比對，從DOS圖中可以知道結構中各個分子的HOMO和LUMO的貢獻度為何。而從電子雲分佈圖可以發現各結構HOMO和LUMO的電子雲分佈情形。 Oligothiophene-functionalized 9,9’-spirobifluorene derivates exhibit good solubility in polar organic solvents and have good thermal stability. thiophene is a high π-electron conjugated structure. It can be applied for the organic semi-conductor material, OLED, PLED, and OFET. In this study, the geometrical structures and electronic properties of 9,9’-Spirobifluorene derivates is studied using the density functional theory with B3LYP functional. Calculated the orbital energies of HOMO, LUMO, and energy gap(Egap). According to my calculating result, the HOMO, LUMO energy levels are tuned with the increase of the thiophene ring owing to the enhanced π-electron delocalization and the increasing conjugation length. The HOMO, LUMO, Egap has the same tendency with the experimental value. Final we use Density of states to find the contribution from HOMO and LUMO of all derivates structure. This study provide a sample and satisfying method, which may be applied to design new materials.
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