本論文可分為三部分，第一部分為將我們先前成功開發出的多環稠合共平面結構單元-茚並菲 (indenophenanthrene)當作核心，在其兩端接上推電子基團形成一系列條型的模型分子，並探討不同π -共軛長度與核心結構對分子之線性與非線性光學性質的影響。第二部分為開發一系列含有吡喃 (pyran) 與1,3 -茚滿二酮 (1,3 -indandione) 結構單元之紅外光染料，並探討不同拉電子基團對其光學性質的影響。第三部分為針對含茚並喹喔啉 (indenoquinoxaline) 結構單元之各類模型分子進行非線性吸收性質量測並探討不同π -共軛系統對這些模型分子之多光子吸收性質的影響。我們對各類模型分子進行線性光學與非線性光學性質量測，其中線性光學實驗包括量測模型分子的吸收光譜、螢光光譜、螢光量子產率與螢光生命期；而非線性光學實驗包括雙光子與三光子吸收光譜、能量依賴性與吸收過程級數光譜的量測。經過分析與探討分子結構與其光學性質，可以得到以下幾種關聯性： [1] 對同一類模型分子而言，分子的共軛特性與其雙光子及三光子吸收效率間可能分別存在著不同的關聯性。例如：分子的共軛長度增加有助於明顯提升雙光子吸收表現，然而共軛結構共平面性的增加才能有效地提升三光子吸收表現。 [2] 分析多叉型模型分子的雙光子及三光子性質與分子結構間的關係，我們觀察到以目前增加分支數目的方式確實可以提升分子的雙光子吸收效率，但是對同一分子的三光子吸收表現卻難以有效提升。此結果顯示雙與三光子吸收效率的提升可能對分子結構上的要求或許存在著本質上的差異性。 [3] 將雜環結構或稠合雜環結構單元如喹喔啉 (quinoxaline)、咔唑 (carbazole)、吡啶并吡嗪 (pyridopyrazine) 及pyrazinocarbazole加入模型分子系統有助於提升雙光子吸收與三光子吸收效率。 [4] 以碳-碳參鍵作為共軛系統之π -電子橋樑可以有效提升雙光子吸收與三光子吸收表現，其中碳-碳參鍵的位置與數目對於三光子吸收有不同程度的影響。 ;Three diiferent model molecular systems are characterized for their linear and multi-photon adsorption properties in this thesis. The first model system is derived from a polycyclic indenophenathrene. Using such a unit we have constructed two linear-type conjugated structures. For the second model system, a series of red-infrared emitting chromophores using pyran and 1,3-indandione as different electron-withdrawing groups have been designed and synthesized. The third model system contains various quinoxalinoid chromophores which are either previously synthesized by former lab members or provided by our collaborator (Prof. Y.-J. Cheng, THU). For the linear optical property measurements, we have performed linear absorption spectra, fluorescence spectra, fluorescence quantum yield and fluorescence lifetime measurements via corresponding spectrometers. On the other hand, we have utilized a wavelength tunable femtosecond laser system as the major light source to probe the two- and three-photon related properties of these model systems. From the measured results, several features should be noted: (1) From the investigated model systems, it is found that the same conjugated structure may cause different influence on the molecular two-photon and three-photon absorption (2PA & 3PA) properties. For instance, increasing the conjugation length may be saliently favorable for the promotion of 2PA whereas enhancing the overall coplanarity of the molecule would be more important for 3PA. (2) There should be a fundamental difference between the molecular designs for the construction of highly two-photon active and three-photon active structures. (3) Introducing hetercyclic units such as quinoxaline, carbazole, pyridopyrazine and pyrazinocarcazole is beneficial for the enhancement of molecular 2PA and 3PA. (4) It is found that the ethynyl linkage is a very efficient functional group for the promotion of 2PA and 3PA. In addition, the position and number of this functional group in a molecule is particularly essential for molecular 3PA.
