Photoinduced electron transfer in self-assembled monolayers of porphyrin-fullerene dyads on ITO
Photoinduced electron transfer in self-assembled monolayers of porphyrin-fullerene dyads on ITO
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DOI：
10.1021/la0500833
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发表时间：
2005-07-05
期刊：
影响因子：
3.9
通讯作者：
Lemmetyinen, H
中科院分区：
文献类型：
--
作者：
Chukharev, V;Vuorinen, T;Lemmetyinen, H
合成了两种卟啉-富勒烯二元体系，分别以ITO-卟啉-富勒烯和ITO-富勒烯-卟啉为取向在ITO电极上形成自组装膜。所述二联体含有两个连接体，用于连接卟啉和富勒烯部分并使它们基本上具有供体-受体对的相似几何形状，以及两个连接体，用于确保二联体以两个所需的相反取向附着到ITO表面。瞬态光电压响应（麦克斯韦位移电荷）被测量的二元膜覆盖的绝缘LB膜，从而确保二元只与ITO电极相互作用。电子转移的方向是从光激发的二分体到ITO的二分体取向无关。的ITO-富勒烯-卟啉结构，其中的主要分子内的电子转移方向与最终的电子转移的二分体的ITO的方向相一致，是25倍强于相反的ITO-卟啉-富勒烯取向的二分体。然而，在液体电化学电池中的静态光电流测量仅显示出较小的取向效应，表明光电流的产生是由SAM-液体界面处的过程控制的。
Two porphyrin-fullerene dyads were synthesized to form self-assembled monolayers (SAMs) on indium-tin oxide (ITO) electrode, with either ITO-porphyrin-fullerene or ITO-fullerene-porphyrin orientations. The dyads contain two linkers for connecting the porphyrin and fullerene moieties and enforcing them essentially to similar geometries of the donor-acceptor pair, and two linkers to ensure the attachment of the dyads to the ITO surface with two desired opposite orientations. The transient photovoltage responses (Maxwell displacement charge) were measured for the dyad films covered by insulating LB films, thus ensuring that the dyads interact only with the ITO electrode. The direction of the electron transfer was from the photoexcited dyad to ITO independent of the dyad orientation. The response amplitude for the ITO-fullerene-porphyrin structure, where the primary intramolecular electron-transfer direction coincides with the direction of the final electron transfer from the dyad to ITO, was 25 times stronger than that for the opposite ITO-porphyrin-fullerene orientation of the dyad. Static photocurrent measurements in a liquid electrochemical cell, however, show only a minor orientation effect, indicating that the photocurrent generation is controlled by the processes at the SAM-liquid interface.