標題: Femtosecond Transient Absorption of Zinc Porphyrins with Oligo(phenylethylnyl) Linkers in Solution and on TiO2 Films
作者: Chang, Chih-Wei
Luo, Liyang
Chou, Chung-Kung
Lo, Chen-Fu
Lin, Ching-Yao
Hung, Chen-Shiung
Lee, Yuan-Pern
Diau, Eric Wei-Guang
應用化學系
應用化學系分子科學碩博班
Department of Applied Chemistry
Institute of Molecular science
公開日期: 9-Jul-2009
摘要: We measured femtosecond transient absorption of dye solutions and TiO2 films sensitized with two zinc porphyrins (PE1 and PE4) to investigate the interfacial dynamics of electron transfer in relation to the dependence of cell performance on the length of the linker (Lin, C.-Y.; Lo, C.-F.; Luo, L.; Lu, H.-P.; Hung, C.-S.; Diau, E. W.-G. J. Phys. Chem. C 2009, 113, 755-764). For both porphyrins adsorbed on TiO2 films with S-1 excitation (lambda(ex) = 620 nm), the transient absorption kinetics probed at 630 nm and 4.9 mu m are complementary to each other because only the excited-state and ground-state species were observed at 630 nm whereas only the charge-separation intermediates were observed at 4.9 mu m. The transient of the PE1/TiO2 film shows a single exponential decay with a large offset, whereas the transient of the PE4/TiO2 film displays a biexponential decay with a small offset. Because of the existence of an additional ps component, the amount of free delocalized electrons (offset signal) in PE4/TiO2 is smaller than that in PEI/TiO2. Our results imply that back electron transfer at the TiO2/dye interface is an important factor to be considered to account for the cell performance of a device.
URI: http://dx.doi.org/10.1021/jp810580u
http://hdl.handle.net/11536/149800
ISSN: 1932-7447
DOI: 10.1021/jp810580u
期刊: JOURNAL OF PHYSICAL CHEMISTRY C
Volume: 113
起始頁: 11524
結束頁: 11531
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