My oral presentation at JCS spring meeting-2012, Tokyo.
非対称スクアリル色素におけるアンカーの影響と光増感作用 Influence of Nature of Anchoring Group inPhotosensitization Behaviour of Unsymmetrical Squaraine DyesGururaj M. Shivashimpi, Shyam S. Pandey, Rie Watanabe, Yuhei Ogomi, Yoshihiro Yamaguchi and Shuzi Hayase Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu 808-0196, JapanNippon Steel Chemical Co. Ltd., 46-80 Nakabaru, Sakinohama, Tobata, Kitakyushu 804-8503, Japan
Working Principle of DSSCs Ti Ti O O CO CO e e N N HO OC N N CO OH Ru e e OHP257 SCN NCS e - Efficiency > 10 % 3I e e I - e 3 TiO2 TiO2 e e 10-20nm e TiO2 layer: 10-20 μm Pt/SnO2/F e eSnO2/F Electrolyte layer: 30 μm
Development of NIR Dyes ! Potentiality of Phthalocyanine, Cyanine and Squaraine sensitizers1. Sharp, narrow and Intense light absorption2. High molar extinction coefficient3. Capability of sensitization of wide band gap semiconductors4. Possibility to tailor the optical absorption window from visible to NIR wavelength region
DSSCs based on Squaraine dyes ! SQ-5 Efficiency = 3.5 % Efficiency = 1.04 % IPCE edge = 750 nm IPCE edge = 700 nm Pandey S. P., et al; J. Photochem. Photobiol., A.; 214, 269-275, 2010 SQ-7 Efficiency = 2.08 % IPCE edge = 690 nm Efficiency = 4.5 % Alex S., et al; IPCE edge = 700 nm J. Photochem. Photobiol., A.; Yum et al; J. A. Chem. Soc.; 129, 10320-10321, 2007 172, 63-71, 2005
Advantage of Cyanoacrylate Anchoring Group ! YR-6 Y-R. Shi, et al; Angew. Chem.; 123, 6749-6751, 2011Chang, W. K., et al; Org. Lett.; 13, 3880-3883, 2011
Squaraine dyes under present investigation ! SQ-8 SQ-83 SQ-84
Synthesis of SQ-83Purity: 98% (By HPLC)FAB-MS: 575.2861 (Observed), 575.2784 (Calculated)Structure confirmed by 1H-NMR
Conclusions:1. Novel Indole donor based unsymmetrical squaraine dyes with varying anchoring groups have been synthesized and characterized.2. Cyanoacrylate functionality leads not only to the red-shift in absorption spectra but pronounced spectral broadening as well as photon harvesting as compared to –COOH anchoring group.3. Introduction of additional spacer between cyanoacrylate anchoring group and conjugated chromophore leads to hampered photon harvesting.