中文摘要 本論文主要利用五苯荑分子結構剛硬的特性與異參茚并苯結構具有π-共軛性質，探討其衍生物的分子內與分子間能量轉移的行為。據此，我們設計出化合物D1和D2作為能量予體，化合物A1和A2作為能量受體，化合物LH則以碳-碳參鍵將能量予體與能量受體連結。 化合物A1及A2在氯仿溶液中的螢光量子產率分別為0.87及0.89 ，很適合作為能量受體的發光團。由於立體因素A2比A1在薄膜中具有較小的分子間的電子相互作用。 在D1-A1及D2-A1組合中，我們製作一系列薄膜，其中予體和受體的總莫耳數一定，但比例不同，當予體的比例增高時，有明顯的去聚集現象；另外，由於D1,D2和A2的立體障礙大，降低了D1-A2及D2-A2中分子間聚集及激發雙體產生的作用力。我們也將予體與受體的比例大至20:1時，然而予體的螢光仍然可忽略，表示能量有效地轉移至受體。 化合物LH為樹枝狀結構，乃以六個D1及一個A1連結而成，其吸收度比起它們個別的總吸收度大1.15倍。以305 nm為激發波長時，化合物LH的螢光強度約為A1的4.3倍，顯示有良好的光收成的效果。綜合來說，化合物LH具有很寬的吸收波長範圍、很大分子消光係數、高螢光量子產率及高能量傳遞效率，顯示此類結構具有很大的潛力作為能量收集器及螢光感應器材料方面的應用。 Abstract This thesis reports the intermolecular excited energy transfer behavior between the donor D1 or D2 and the acceptor A1 or A2 in thin films and the intramolecular excited energy transfer behavior of compound LH in solutions and in the solid state. The structures of D1, D2, A1, A2, and LH are derived from the rigid pentiptycene and/or isotruxene moieties, where the ethynyl groups are the π-conjugation linkers. The fluorescence quantum yields for A1 and A2 in chloroform are 0.87 and 0.89, respectively, showing that A1and A2 are good fluorophores. Because of the bulky pentiptycene groups, A2 is expected to have little intermolecular π-π interactions. In contrast, A1 forms aggregates in the solid state due to its planar structure. As a result, the fluorescence from the D1-A1 or D2-A1 mixed films depends on the molar fraction of A1 in the thin solid films. However, this phenomenon is not observed for the D1-A2 and D2 –A2 mixed films even when the D:A molar ratio is as larger as 20:1, indicating efficient energy transfer properties in these D-A systems. The dendritic structure of LH consists of six D1 group and one A1 group. However, the molar absorptivity of LH is larger by 1.15 times than the sum of these groups. Upon excitation at 305 nm, the fluorescence intensity of LH is 4.3 times larger than that of A1. In conjunction with the wide absorption spectrum, LH might prove of value for application as light-harvesting or fluorescent sensing materials.
