利用飛秒螢光光譜法研究紫質分子在TiO2與Al2O3奈米薄膜上的介面電子轉移與分子間能量轉換動力學

Abstract

本論文研究主題為利用飛秒螢光光譜法研究一系列高元件效率紫質分子，在TiO2與Al2O3奈米薄膜上的介面電子轉移與分子間的能量轉換。 紫質分子吸附在薄膜上會因為自身π-π作用力堆疊，而造成能量因分子間轉移過程而流失，一直被認為是紫質染料效率無法再提升的主要原因，在本論文中加入了鵝去氧膽酸（CDCA）作為與紫質染料的共吸附劑，以減緩其在薄膜上的堆疊程度。結果發現此一系列分子對加入CDCA有不同的影響，YD-0與YD-1分子在穩態光譜及螢光瞬態光譜中的證據都顯示出CDCA可以減少分子間之能量轉移，因此其電子注入效率會隨CDCA濃度變高而提昇；但從螢光瞬態光譜結果表明CDCA對減少YD-2分子間能量轉移的幫助並不如前兩個分子。而比對此系列染料與CDCA共吸附後之元件效率，結果與我們在瞬態光譜上之量測結果一致。YD-0與YD-1分子與CDCA共吸附時有最佳的元件效率，但YD-2分子在不加入CDCA的情況下效率最佳。

In this Thesis we study interfacial electron transfer and intermolecular energy transfer dynamics of a series of high cell efficiency porphyrins on nanocrystalline TiO2 and Al2O3 films using femtosecond fluorescence spectroscopy. Porphyrins will be self aggregate by π-π interaction on nanocrystalline film, and energy will be loss through intermolecular energy transfer process. This is a problem should be solved in porphyrin based DSSC. We add chenodeoxycholic acid (CDCA) as co-absorbent with porphyrin dyes to reduce the degree of porphyrin aggregation. We found there will be different effect in YD-series porphyrin by adding CDCA as co-absorbent. Our steady-state and femtosecond fluorescence measurement both agree that CDCA can reduce intermolecular energy transfer in YD-0 and YD-1 system, but YD-2 could not. I-V measurement shows cell efficiency of YD-0 and YD-1 will improve by adding CDCA as co-absorbent, but YD-2 not. This shows clear agreement with kinetics results .