透過您的圖書館登入
IP:3.236.139.73
  • 學位論文

以矽烷基為間隔之芳香基高分子之能量轉移途徑

指導教授 : 陳益佳
若您是本文的作者,可授權文章由華藝線上圖書館中協助推廣。

摘要


藉由單一光子計數、飛秒螢光混頻系統與飛秒瞬態吸收光譜等三種時間解析之技術,研究分子在激發態給體與受體間之能量轉移途徑,研究的分子為[(1,1'-biphenyl)-4,4'-diyldi-2,1-ethenediyl]bis(dimethylsilane)單體D 1,[1,2-ethenediylbis(4,1-phenylene-2,1-ethenediyl)]bis(dimethylsilane)單體A 2以及三個共聚物3、4及5[(Donor-SiMe2)n = 1-3-(Acceptor-SiMe2)]m,當n = 1為共聚物1D1A 3,n = 2為共聚物2D1A 4,n = 3為共聚物3D1A 5,給體為1,1'-Biphenyl-4,4'-diethene,受體為1,1'-(1E)-1,2-ethenediylbis[4-ethenyl-Benzene]。 量測得到單體D 1在266 nm波長激發下有兩個遲緩之生命期常數81.7 ± 4.2 ps及681.2 ± 37.5 ps,指認為單體D 1的S2及S1生命期。單體A 2在375 nm波長激發下得到單一自然衰減生命期常數為976.3 ± 11.8 ps,指認為S1之生命期。共聚物1D1A 3、2D1A 4及3D1A 5在激發波長375 nm,解析度約80 ps之條件下,其螢光曲線呈現單一自然衰減,分別為836.7 ± 18.8 ps、873.0 ± 3.0 ps及824.0 ± 2.0 ps,分別指認為共聚物S1生命期。而在使用飛秒螢光混頻技術時間解析為250飛秒條件下,呈現雙自然衰減曲線,短生命期常數分別為118.2 ps、118.5 ps及85.1 ps,指認為共聚物於激發態在溶劑下之振動鬆弛。藉由瞬態吸收光譜的技術在266 nm波長激發,可以瞭解單體與共聚物於電子激發態的吸收波長,得知單體D 1之激發態吸收波長分布於450 nm處,而單體A 2的則分布於660 nm左右,兩者有明顯的差異。而共聚物中,隨著主鏈上給體的比例增加,在紅光區的能量也增加,表示單體D 1將能量傳遞給單體A 2並進行放光,由於數據擷取的步距為5 ps,觀察到受體之生成在5 ps內就已經產生,因此能量傳遞速率應快於2.0×1011 sec-1。利用此三種技術瞭解分子於激發態之能量傳遞,並對於後續實驗得到一個基本結果與輪廓。

並列摘要


Using three techniques including time-correlated single photon counting, femtosecond fluorescence up-conversion and femtosecond transient absorption we study the molecular energy transfer between donor and acceptor. Five molecules [(1,1'-biphenyl)-4,4'-diyldi-2,1-ethenediyl]bis(dimethylsilane) (monomer D 1), [1,2-ethenediylbis(4,1-phenylene-2,1-ethenediyl)]bis(dimethylsilane) (monomer A 2), and copolymers [(Donor-SiMe2)n = 1-3-(Acceptor-SiMe2)]m, 1D1A 3, 2D1A 4 and 3D1A 5 are used. Upon excitation at 266 nm monomer D 1 exhibits bi-exponential behavior on its fluorescence decay curve with the fitted time constants 81.7 ± 4.2 ps and 681.2 ± 37.5 ps. We assign the short component to be the lifetime of the S2 state and the long one to be the S1 state. Following excitation of 375 nm on monomer A 2, it exhibits single exponential decay with a time constant 976.3 ± 11.8 ps. Accordingly we assign that to be the lifetime of the S1 state of A 2. For the copolymers 1D1A 3, 2D1A 4, and 3D1A 5, all of them exhibit biexponential fluorescence decay with fitted fast and slow lifetimes 118.2 ps, 836.7 ± 18.8 ps, 118.5 ps, 873.0 ± 3.0 ps, and 85.1 ps, 824.0 ± 2.0 ps, respectively. We assign the short component to be vibrational relaxation of the excited states of copolymers, and the long component to be the lifetime of the S1 state. The data recorded with the transient absorption spectrometer display an absorption band of D* 1 centered at 660 nm and of A* 2 at 450 nm, respectively. For all three copolymers the rise of A* 2 appearance is faster than (5ps)-1 indicating that the energy from donor to acceptor is very efficient.

並列關鍵字

無資料

參考文獻


3. Tomita, G.; Rabinovitch, E. Biophys. J. 1962, 2, 483.
4. Gratzel, M., Ed “Energy Resources through Photochemistry and Cataylsis” ; Academic Press : New York, 1983.
12. Chen, R. M. Luh, T. Y. J. Am. Chem. Soc., 1997, 119, 11321.
13. Bertolasi, V.; Feretti, V, J. Chem. Soc., Perkin Trans. 2 1993, 213-219.
14. Verhoeven, J. W.; Dirkx, I. P. Tetrahedron 1969, 25, 4037.

延伸閱讀