標題: Preparation and Spectral, Electrochemical, and Photovoltaic Properties of Acene-Modified Zinc Porphyrins
作者: Lin, Ching-Yao
Wang, Yu-Chien
Hsu, Shun-Ju
Lo, Chen-Fu
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: 14-一月-2010
摘要: A series of acene-modified zinc porphyrins (benzene to pentacene, denoted as LAC-1 to LAC-5) were prepared to study their absorption spectra, electrochemical properties, and photovoltaic properties. For the absorption spectral changes in THF, porphyrin B bands are red-shifted and broadened from 449 to 501 nm for LAC-I to LAC-3, showing the effect of additional pi-conjugation. In contrast, the B bands of LAC-4 and LAC-5 are blue-shifted. In addition, the tetracenyl group of LAC-4 gives rise to absorption bands in between B and Q bands. On the other hand, the Q bands of LAC-1 to LAC-5 are systematically broadened and red-shifted from 629 to 751 nm. By comparison, the absorption bands of LAC porphyrins on TiO(2) films are broadened and slightly shifted. Fluorescence emission maxima of LAC porphyrins in THF are also systematically red-shifted from LAC-1 to LAC-5. Cyclic voltammetry experiments in THF/TBAP show that the first reductions are systematically positive-shifted from -1.16 to -0.85 V vs SCE for LAC-1 to LAC-5, indicating the effect of increasing pi-conjugation. As for the performance of DSSCs using LAC porphyrins, the overall efficiency are LAC-1 (2.95%), LAC-2 (3.31%), LAC-3 (5.44%), LAC-4 (2.82%), and LAC-5 (0.10%). Overall efficiency of a LAC-3-sensitized solar cell is nearly twice of that of a LAC-1-sensitized solar cell and is about 81% overall efficiency of N719-sensitized solar cells under the same experimental conditions. The conversion efficiency of incident photons to current (IPCE) experiments shows that the broadened absorption bands of LAC-3 effectively minimizes the gap between B and Q bands, contributing to the improved DSSC performance. The very poor performance of LAC-5 is suggested to be caused by rapid nonradiative relaxation of the molecule in the singlet excited state.
URI: http://dx.doi.org/10.1021/jp909232b
http://hdl.handle.net/11536/5975
ISSN: 1932-7447
DOI: 10.1021/jp909232b
期刊: JOURNAL OF PHYSICAL CHEMISTRY C
Volume: 114
Issue: 1
起始頁: 687
結束頁: 693
顯示於類別:期刊論文


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