具推拉電子基之新穎紫質分子在溶液中與奈米薄膜上的飛秒螢光動力學研究

Abstract

本論文研究具推拉電子基的紫質分子分別在溶液與固相奈米薄膜上的緩解動力學。我們利用飛秒螢光上轉移技術對ZnP1與ZnP2的緩解過程作時間的解析，其中ZnP2具有二苯胺作為推電子基，ZnP1則為對照組，二者的去激化過程有十分明顯的差異。在溶液中，ZnP1的緩解過程與Zewail所發表的ZnTPP十分類似，但是具有二苯胺作為推電子基的ZnP2則出現了分子內電荷轉移的過程。 固相奈米薄膜實驗中，我們比較二者在二氧化鈦與氧化鋁上的衰減速率，藉此計算出二者電子注入的量子產率，並與製成元件後的轉換效率比較，希望能夠有所聯結。同時我們還加入共吸附劑CDCA，希望能夠控制分子間的堆疊，以降低分子間能量轉移的速率，而結果顯示CDCA確實能夠抑制堆疊的產生，並且增加電子注入的量子產率。

The excited-state relaxation dynamics of zinc porphyrins with electron withdrawing and donating group were studied in this thesis. With the application of fluorescence up-conversion technique, the relaxation processes of ZnP1 and ZnP2 upon S2 excitaiton were reported. In ZnP1, the dynamics is similar to the results reported by Zewail et. al. In ZnP2, the result suggests that an additional intramolecular charge transfer occurs between porphyrin moiety and acid group, which causes the significant change of transient We calculate electron injection yield by comparing excited-state lifetime of each zinc-porphyrins on both TiO2 and Al2O3 solid nanocrystalline films, the relationship between injection yield and efficiency is discussed. Mixing coadsorbate CDCA, which lowering the rate of intermolecular energy transfer, also controls aggregation of porphyrins on solid nanocrystalline films. The results show higher electron injection yield with higher concentration of CDCA.