Fluorene-containing organic photosensitizers for dye-sensitized solar cells

Please use this identifier to cite or link to this item: https://ir.lib.ncu.edu.tw/handle/987654321/100343

Title:	Fluorene-containing organic photosensitizers for dye-sensitized solar cells
Authors:	吳春桂;Wu, Chun-Guey;Chung, Ming-Fong;Tsai, Hui-Hsu Gavin;Tan, Chun-Jui;Chen, Su-Chien;Chang, Chiao-Hsin;Shih, Ting-Wen
Contributors:	理學院化學學系
Keywords:	density functional calculations;energy conversion;organic dyes;sensitizers;solar cells
Date:	2012-09-01
Issue Date:	2026-04-21 13:58:22 (UTC+8)
Publisher:	Wiley-VCH Verlag;Weinheim: WILEY-VCH Verlag
Abstract:	摘要： Seven new donor–spacer–acceptor metal‐free organic dyes containing a fluorene and/or thiophene unit as a conjugated spacer are prepared and their physicochemical properties as well as photovoltaic performance are studied. The electron transfer from donor to acceptor upon excitation of these dyes is sensitive to the conjugated spacers. If a stronger donor moiety such as (ethylenedioxy)thiophene is used as a spacer, such as in F‐E1 dye, the dye molecule has a better charge separation and therefore high efficiency. Furthermore, for the same donor and acceptor, fluorene is a better conjugated spacer than the bithiophene moiety because of its nonplanar conformation, which avoids the electron–hole recombination of dye upon photoexcitation. Short molecules with planar conformation aggregate easily, and the corresponding device reveals low open‐circuit voltage Voc. On the other hand, dye molecules with long alkyl side chains (large size) adsorb less on the TiO2 electrode, which results in a smaller short‐circuit current density Jsc. The difference in the efficiency of these dyes is small except for F‐1 (owing to its short conjugation length), and electron density difference map analyses reveal that photoexcitation transfer of electron density from the donating moieties toward the acceptor/anchoring units occurs for all molecules. The small difference in the efficiency is attributed partly to the degree of effective charge transfer upon excitation, not totally to the absorption profile of the dye molecules. Furthermore, time‐dependent DFT simulated absorption spectra are in excellent agreement with experimental spectra when the dyes are in their protonated states in THF solution. The transition probability calculated with the electron density difference analyses combined with the absorption data and photovoltaic performance provide useful information for designing organic sensitizers for dye‐sensitized solar cells. Catch the sun: Seven new donor–spacer–acceptor metal‐free organic dyes containing a fluorene and/or thiophene unit as a conjugated spacer have been prepared and their photovoltaic performance studied (see a selection of structures). Theoretical calculations suggest that the small difference in the efficiency of these sensitizers is attributable partly to the degree of effective charge transfer upon excitation, not totally to the absorption profile of the dye molecules. 其他題名： ChemPlusChem 出版者： Weinheim: WILEY-VCH Verlag 出版日期： 2012-09 出處： ChemPlusChem (Weinheim, Germany), 2012-09, Vol.77 (9), p.832-843 版權： Copyright © 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim 識別號： ISSN: 2192-6506 識別號： EISSN: 2192-6506 識別號： DOI: 10.1002/cplu.201200127
Appears in Collections:	[Department of Chemistry] journal & Dissertation

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