Thieno[3,4‐b]thiophene‐Based Organic Dyes for Dye‐Sensitized Solar Cells |
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| Authors: | Yung‐Chung Chen Hsien‐Hsin Chou Ming Chih Tsai Sheng‐Yu Chen Jiann T. Lin Ching‐Fa Yao Kellen Chen |
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| Affiliation: | 1. Institute of Chemistry, Academia Sinica, 11529, Nankang, Taipei (Taiwan), Fax: (+886)?783‐1237;2. Department of Chemistry, National Taiwan Normal University, 117, Taipei (Taiwan);3. AU Optronics Corporation, 30078, Hsinchu (Taiwan) |
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| Abstract: | New dipolar sensitizers containing an ethyl thieno[3,4‐b]thiophene‐2‐carboxylate (ETTC) entity in the conjugated spacer have been synthesized in two isomeric forms. These compounds were used as the sensitizers of n‐type dye‐sensitized solar cells (DSSCs). The best conversion efficiency (5.31 %) reaches approximately 70 % of the N719‐based (7.41 %) DSSC fabricated and measured under similar conditions. The ETTC‐containing compounds exhibit a bathochromic shift of the absorption compared to their thiophene congeners due to the quinoid effect, however, charge‐trapping at the ester group of ETTC was found to jeopardize the electron injection and lower the cell efficiency. Charge trapping is alleviated as the ester group of ETTC is replaced with a hydrogen atom, as evidenced from the theoretical computation. |
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| Keywords: | dye‐sensitized solar cells electron transfer metal‐free sensitizers quantum chemistry quinoids |
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