本實驗室先期研究開發出一系列新的線型共軛分子1,4-二噻吩萘，其吸收光譜及螢光光譜範圍分別為340~393 nm及471~553 nm，且具有極大的斯托克斯位移(122~174 nm)。因此本研究結合先期研究系列化合物的特徵，重新設計並合成一系列具1,4-二(2,2’-聯噻吩-5-基)萘的新型非極性大斯托克斯位移分子，且以”正己烷基”提升分子的溶解度，以利於合成較大結構分子。這些分子產生大斯托克斯位移的原由，是來自於分子基態及激發態產生的幾何構形差異，而非電荷分布變化的分子內電荷轉移效應，因此光譜能不受溶劑效應影響及在高極性溶劑仍維持良好螢光的特性，同時設計更多共軛性使這系列分子具備更長波長的吸收與放光。
本研究以1,4-二(2,2’-聯噻吩-5-基)萘為中心骨架，合成四個目標化合物，並使用儀器測量分子的吸收光譜、螢光光譜、螢光量子產率及消光係數等光物理性質，探討大斯托克斯位移與共軛分子結構之間的關係。

Our laboratory had developed a series of new linear conjugated molecules, 1,4-diarylnaphthalene, with 340~393 nm wavelength of absorption spectra, and 471~553 nm wavelength of fluorescence spectra. These molecules have 122~174 nm Stokes shift. Based on our previous study, this study have synthesized a series of non-polar large Stokes shift molecules with 1,4-bis(2,2'-bithiophen-5-yl) naphthalene skeleton and introduce n-hexyl group to improve the solubility of molecules. We have synthesized more higher molecules weight due to the solubility of compounds. These molecules produce large Stokes shifts is not intra-molecular charge transfer but geometry relaxation. Therefore, the spectra is not affected by the solvent effect and keeping good fluorescence in high polar solvent. Simultaneously, designing more conjugation makes the series of molecules have longer wavelength absorption and emission.
In this study, we use 1,4-bis(2,2'-bithiophen-5-yl)naphthalene as the central skeleton to synthesize four target compounds and use instruments to measure their absorption spectrum, fluorescence spectrum, fluorescence quantum yield and extinction coefficient. Furthermore, using theoretical calculation software to calculate Highest Occupied Molecular Orbital(HOMO)/Lowest Unoccupied Molecular Orbital (LUMO). Obtain foregoing data to realize and discuss the relationship between Large Stokes Shift and conjugated molecular structure.

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