近年來科學家們對於利用低能量的光產生高能量的光產生興趣，其中一種方法便是利用發光團吸收低能量的入射光，經由系統間跨越後將能量轉移至另一個發光團，並且由三重態-三重態消滅機制(triplet-triplet annihilation，TTA)而產生上轉移螢光。 本實驗以rose bengal衍生物為敏化劑，分別設計兩個發光體，在四氫呋喃和甲醇混合溶液中組合成此能量上轉移系統。一個是利用長碳鏈連結兩個發光單體的DMEPA (1,4-bis(2,4,6-trimethyl-3-((10-phenylanthracen-9-yl) ethynyl)phenyl) butane)，增加其分子碰撞的機會，探討是否有分子內三重態消滅的存在，使得此系統於稀濃度下仍有一定的上轉移螢光表現。此外設計了tBEPA (9-(3,3-dimethylbut-1-yn-1-yl)-10-phenyl-anthrancene)發光體，探討分子結構的改變對其光物理性質及上轉移系統中的影響。 本實驗中兩個系統皆以568 nm激發rose bengal，分別在450 nm 及425 nm可看到DMEPA及tBEPA的上轉移螢光，最佳上轉移螢光量子產率分別為0.0021及0.0052。此外將DMEPA系統與之前實驗室所研究的MEPA、BMEPA系統做比較，發現DMEPA的結構設計無法明顯看到分子內TTA的效果，從發光體濃度與螢光強度的關係來推測，DMEPA於低濃度下存在著分子內的自我淬息使得效果不如預期。 In recent years, scientists are interested in energy upconversion, i.e., the generation of higher energy photons with respect to incident light. Photon upconversion via triplet-triplet annihilation is a possible way. In our work, we used rose bengal derivative as sensitizer and designed two emitters to investigated this upconversion systems in MeOH/THF solution. The emitter, DMEPA (1,4-bis(2,4,6-trimethyl-3-((10-phenylanthracen-9-yl)- ethynyl)phenyl) butane), is composed of two monomers linked by a long carbon chain. The structure was originally considered to improve the collision possibility, so that we can observe delay fluorescence in dilute concentration. And tBEPA (9-(3,3-dimethylbut-1-yn-1-yl)-10-phenylanthrancene) was also designed to decrease the reabsorbance by sensitizer and investigate the photophysical properties in upconversion system. In these two systems, we can see delay fluorescence at 450 nm and 425 nm respectively using 568 nm incident radiation. And each of the upconvesion quantum yield is 0.0021 and 0.0052. Moreover, we couldn’t observe intramolecular triplet-triplet annihilation as expected in DMEPA system. The phenomenon may be ascribed to intramolecular self-quenching in dilute concentration.
