透過您的圖書館登入
IP:18.232.88.17
  • 學位論文

有機發光材料之結構與電子性質理論計算研究

Theoretical Study of Structures and Electronic Properties of Organic Electroluminescene Materials

指導教授 : 王伯昌

摘要


利用MOPAC之AM1方法,計算有機發光材料基態與激發態時結構,並搭配Gaussian的ZINDO方法計算分子之吸收與放射波長,並針對結構、分子軌域圖形與態密度結構去了解這些分子的光電特性。在本研究中,我們計算順丁烯亞醯胺(maleimide)與其衍生物的吸收、放射波長、分子結構、分子軌域圖形與態密度結構,並比較其Stokes shift值改變程度與結構、分子軌域的關係。 由計算的結果可以知道推電子的取代基對吸收與放射波長有紅位移的影響,而拉電子的取代基則是對吸收波長有藍位移的影響,藉由這個原因,使得各個衍生物的Stokes shift大小有所改變,進而可以利用這個關係調整所需的發光顏色。另外從結構上可以發現,3,4-位置上的取代基分子大小對於吸收波長與放射波長有一定的關係。3,4-位置上的取代基分子比較大時基態的吸收波長也比較大,而在放射波長部分,由於立體障礙的關係,在計算上放射波長也會得到較大的波長。在分子軌域圖形上,有較大的Stokes shift分子,分子軌域圖形都與MLH分子相似。在基態的HOMO時,分子軌域都定域化在3,4-位置的取代基上,基態的LUMO集中在maleimide分子上,激發態HOMO與基態的HOMO分佈情形差不多,激發態的LUMO集中在maleimide分子與3,4-位置取代基的第一個環上。若激發態的LUMO與基態的LUMO分佈情形相似的話,其Stokes shift會較小於MLH分子。接著也選用一些具有高潛力的有機發光材料,來與maleimide分子結合,並預測其吸收與放射波長,以利實驗家挑選所需的有機發光材料分子。 另外本論文也使用相同的計算流程方法來計算對位三聯苯分子的光電特性。由其氰基的取代位置與結構來討論其與吸收、放射波長的關係。

並列摘要


The semi-empirical and ab initio methods were used to investigate the absorption wavelength, emission wavelength, geometric and electronic structures of maleimide derivatives. According to the calculation results, the absorption and emission wavelength will bathochromic shift with electron-donating group substitution such as MLH, MLMe, 4-MeOMLH, 4-MeOMLMe, 2-THPMLH and hypsochromic shift with electron-withdrawing group substitution such as 3-CF3MLH, 4-CF3MLH and 3-PYDMLH. The ground state and excited stated structure also influence the wavelength. The dihedral angle between maleimide and substitution group play an important role in wavelength calculation. In molecular orbital calculation, the delocalized LUMO in excited state prefer large Stokes shift. We also calculated the p-terphenyl and its derivatives by ZINDO/MOPAC and DFT method. To investigate the substitution effect, n-hexyloxyl, 2-ethylhexyloxyl, methoxyl and CN substituents were attached onto p-terphenyl in order to generate their maximum absorption and emission wavelength, respectively. The steric effects generate the maximum absorption and emission wavelength shifts and the CN group at the central phenyl with ortho-substitution and at peripheral phenyl ring with para-substitution will influence maximum excitation wavelengths significantly.

參考文獻


[83]. 程長遠, 分子模擬聚合物分子在固體表面的吸附現象與液態層析法的分離機制(博士論文), 淡江大學化學研究所,1999
[125]. M. S. Miao, P. E. Van Camp, and V. E. Van Doren, J. Chem. Phys. 109, 9623 (1998).
[50]. J. Shi, C. W. Tang, and C. H. Chen, US Patents, 5935721 (1999).
[43]. G. Rajeswaran, M. Itoh, M. Boroson, S. Barry, T. K. Hatwar, K. B. Kahen, K. Yoneda, R. Yokoyama, T. Yamada, N. Komiya, H. Kanno, and H. Takahashi, SID ’00 Digest, 40, 1 (2000).
[122]. F. T. Luo, Y. T. Tao, S. L. Ko, C. H. Chuen, and H. Chen, J. Mater. Chem. 12, 47 (2002).

延伸閱讀