Unsymmetrically Substituted Donor–π–Acceptor‐Type 5, 15‐Diazaporphyrin Sensitizers: Synthesis, Optical and Photovoltaic Properties. Issue 5 (24th February 2017)

• Record Type: Journal Article
• Authors: Omomo, Satoshi; Tsuji, Yukihiro; Sugiura, Kenichi; Higashino, Tomohiro; Nakano, Haruyuki; Imahori, Hiroshi; Matano, Yoshihiro
• Is Part Of: ChemPlusChem. Volume 82:Issue 5(2017)
• Page Start: 695
• Page End: 704
• Publication Date: 2017-02-24
• Subjects: donor–acceptor systems -- dyes/pigments -- electrochemistry -- porphyrinoids -- sensitizers; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/cplu.201700051
• Languages: English
• ISSNs: 2192-6506

Abstract

Abstract: The first examples of unsymmetrical β‐substituted donor–π–acceptor (D–π–A)‐type 5, 15‐diazaporphyrin (DAP) sensitizers with both p ‐aminophenyl and p ‐carboxyphenyl groups at their peripheral 3‐, 7‐, 13‐, and/or 17‐positions have been synthesized for use in dye‐sensitized solar cells (DSSCs). UV/Vis absorption and emission spectroscopy, electrochemical measurements, and DFT calculations revealed that these D–π–A dyes exhibit high light‐harvesting properties over the whole visible range because of the intrinsic charge‐transfer character of their electronic transitions. The cell performances of TiO2 ‐based DSSCs fabricated with the newly prepared DAP derivatives were evaluated under standard AM1.5 conditions. Among the four dyes examined, 13, 17‐bis( p ‐carboxyphenyl)‐3, 7‐bis[ p ‐( N, N ‐dimethylamino)phenyl]‐DAP showed the highest power conversion efficiency (2.0 %), which was 20 times larger than that obtained with 3‐( p ‐carboxyphenyl)‐DAP. These results show that the DAP chromophore could be used as the electron‐accepting π unit in various types of functional dyes. Abstract : Not like looking in a mirror ! Unsymmetrical β‐substituted donor–π–acceptor‐type 5, 15‐diazaporphyrins (DAPs; see scheme) exhibit high light‐harvesting properties over the whole visible range because of the intrinsic charge‐transfer character of the electronic transitions. Dye‐sensitized solar cells composed of the new dyes have power conversion efficiencies of up to 2.0 %; these are among the highest values ever reported for DAP sensitizers.