Effects of porphyrin substituents on film structure and photoelectrochemical properties of porphyrin/fullerene composite clusters electrophoretically deposited on nanostructured SnO2 electrodes.
Effects of porphyrin substituents on film structure and photoelectrochemical properties of porphyrin/fullerene composite clusters electrophoretically deposited on nanostructured SnO2 electrodes.
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DOI：
10.1002/chem.200700446
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发表时间：
2007-12
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通讯作者：
H. Imahori;M. Ueda;Soonchul Kang;H. Hayashi;S. Hayashi;H. Kaji;S. Seki;A. Saeki;S. Tagawa;T. Umeyama;Y. Matano;Kaname Yoshida;S. Isoda;M. Shiro;N. Tkachenko;H. Lemmetyinen
中科院分区：
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作者：
H. Imahori;M. Ueda;Soonchul Kang;H. Hayashi;S. Hayashi;H. Kaji;S. Seki;A. Saeki;S. Tagawa;T. Umeyama;Y. Matano;Kaname Yoshida;S. Isoda;M. Shiro;N. Tkachenko;H. Lemmetyinen
我们系统地研究了中四苯基卟啉对薄膜结构的取代效应，以及游离基卟啉和C（60）复合簇电泳沉积在纳米结构SnO(2)电极上的光电化学性质。光电流产生效率与卟啉对C（60）的络合能力有关。基本上，入射光子电流效率（IPCE）值随着膜中卟啉相对于C（60）的相对量的增加而增加。由于卟啉在SnO(2)电极上具有简单而特异的取代基（即四苯基卟啉（3,5- ometpp； TPP=四苯基卟啉）的中苯基环的位元位置上的甲氧基基团）和C（60）的独特分子排列，使得该类型的光电器件的IPCE值最大（约60%）。3,5- ometpp和C（60）在混合溶剂中快速结合形成复合簇和微晶体是独一无二的，因为除了卟啉/C（60）和C（60）分子之间的pi-pi相互作用外，卟啉的甲氧基和卟啉/C（60）之间的分子间相互作用（即氢键和CH-pi相互作用）加速了这种结合。由卟啉和C（60）组成的薄膜和单晶都表现出非常高的电子迁移率(7 × 10（-2）和0.4 cm(2) V(-1) s(-1))，这与高效体异质结太阳能电池的电子迁移率相当。我们的实验结果成功地证明了纳米结构的电子和空穴传输途径在体异质结太阳能电池中的重要性。这一发现将在分子水平上为分子光伏的设计提供基础和有价值的信息。
We have systematically examined the substituent effects of meso-tetraphenylporphyrins on film structures and the photoelectrochemical properties of the composite clusters of free-base porphyrin and C(60) electrophoretically deposited on nanostructured SnO(2) electrodes. The photocurrent generation efficiency was found to correlate with the complexation ability of the porphyrin for C(60). Basically, the incident photon-to-current efficiency (IPCE) value was increased with increasing relative amounts of the porphyrin versus C(60) in the films. The unique molecular arrangement of the porphyrin with the simple, specific substituents (i.e., methoxy groups at the meta-positions of the meso-phenyl rings of tetraphenylporphyrins (3,5-OMeTPP; TPP=tetraphenylporphyrin)) and C(60) on SnO(2) electrodes resulted in the largest IPCE value (ca. 60 %) among this type of photoelectrochemical device. The rapid formation of the composite clusters and microcrystals from the combination of 3,5-OMeTPP and C(60) in a mixed solvent is unique as the association is accelerated by intermolecular interactions (i.e., hydrogen-bonding and CH-pi interactions) between the methoxy groups of the porphyrins and the porphyrin/C(60), in addition to the pi-pi interactions between the porphyrins/C(60) and C(60) molecules. Both the films and single crystals composed of the porphyrin and C(60) exhibited remarkably high electron mobility (7x10(-2) and 0.4 cm(2) V(-1) s(-1)), which is comparable to the value for highly efficient bulk heterojunction solar cells. Our experimental results have successfully demonstrated the importance of nanostructured electron- and hole-transporting pathways in bulk heterojunction solar cells. Such a finding will provide basic and valuable information on the design of molecular photovoltaics at the molecular level.