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D–π–A Structured Zn II ‐Porphyrin Dyes with Thiophene Moiety for Highly Efficient Dye‐Sensitized Solar Cells
Author(s) -
Kang Sung Ho,
Kang Min Soo,
Choi In Taek,
Hong Ji Yeoun,
Ju Myung Jong,
Kim Hwan Kyu
Publication year - 2014
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201300075
Subject(s) - porphyrin , dye sensitized solar cell , thiophene , alkyl , moiety , photochemistry , absorption (acoustics) , materials science , chemistry , absorption spectroscopy , zinc , solar cell , energy conversion efficiency , organic chemistry , optoelectronics , electrode , physics , quantum mechanics , electrolyte , composite material
Abstract Herein, we design and synthesize a new D–π–A zinc porphyrin, enveloped with a long alkyl thiophene unit (Th‐ZnP‐CNCOOH, TP), for dye‐sensitized solar cells. The long alkyl‐substituted thiophene unit is incorporated into the porphyrin dye to red‐shift its absorption wavelength. The effects of the alkyl thiophene moiety at the meso ‐position of the zinc porphyrin on the optical, electrochemical, and photovoltaic properties of the material are investigated. Dye‐sensitized solar cells (DSSCs) prepared using the new dye, co‐adsorbed with a simply structured organic co‐adsorbent (HC‐A4), are fabricated. The obtained TP/HC‐A4‐sensitized DSSCs exhibit a remarkable enhancement in both short‐circuit current ( J SC ) and open‐circuit voltage ( V OC ), relative to the corresponding single‐dye DSSCs, which can be attributed to a combination of the light‐harvesting effect from their complementary absorption behavior and the slow charge‐recombination process. The device based on TP/HC‐A4 co‐sensitization yields: J SC =14.4 mA cm −2 , V OC =0.62 V, a fill factor FF=0.75 and an efficiency η =6.7 %. This performance is superior to those of devices containing either TP ( η =2.4 %) or HC‐A4 ( η =2.8 %), fabricated under the same conditions. The present study indicates that the prevention of dye aggregation, as well as complementary absorption spectra of the porphyrin dyes using co‐sensitizers, are key to improving the device performance.