my oral presentation at jcs spring meeting-2012, tokyo
DESCRIPTION
92nd Japanese Chemical Society Spring Meeting-2012, oral presentation on influence of nature of anchoring group in photo sensitization behavior of unsymmetrical squaraine dyesTRANSCRIPT
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 in
Photosensitization Behaviour of Unsymmetrical
Squaraine Dyes
Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu 808-0196, Japan
Nippon Steel Chemical Co. Ltd., 46-80 Nakabaru, Sakinohama, Tobata, Kitakyushu 804-8503, Japan
Gururaj M. Shivashimpi, Shyam S. Pandey, Rie Watanabe,
Yuhei Ogomi, Yoshihiro Yamaguchi and Shuzi Hayase
Working Principle of DSSCs
SnO2/F
3 I-
I3-
Pt/SnO2/F TiO2 layer: 10-20 μm
Electrolyte layer: 30 μm
TiO2
10-20nm
TiO2
Ru N
N
C O
C O O H
O
Ti
N
N
C O
H O O C
O
Ti
S C N N C S OHP257
e
e
e e
e
e
e
e
e
e
e
e
e
Efficiency > 10 %
Efficiency > 10 %
Development of NIR Dyes !
Potentiality of Phthalocyanine, Cyanine and
Squaraine sensitizers
1. Sharp, narrow and Intense light absorption
2. High molar extinction coefficient
3. Capability of sensitization of wide band gap semiconductors
4. Possibility to tailor the optical absorption window from
visible to NIR wavelength region
DSSCs based on Squaraine dyes !
Efficiency = 4.5 %
IPCE edge = 700 nm
Yum et al; J. A. Chem. Soc.; 129, 10320-10321, 2007
Efficiency = 3.5 %
IPCE edge = 750 nm
Pandey S. P., et al;
J. Photochem. Photobiol., A.;
214, 269-275, 2010
SQ-5
Efficiency = 1.04 %
IPCE edge = 700 nm
SQ-7
Efficiency = 2.08 %
IPCE edge = 690 nm
Alex S., et al;
J. Photochem. Photobiol., A.;
172, 63-71, 2005
Advantage of Cyanoacrylate Anchoring
Group !
YR-6
Chang, W. K., et al; Org. Lett.; 13, 3880-3883, 2011
Y-R. Shi, et al;
Angew. Chem.; 123, 6749-6751, 2011
Squaraine dyes under present investigation !
SQ-83
SQ-8
SQ-84
Synthesis of SQ-83
Purity: 98% (By HPLC)
FAB-MS: 575.2861 (Observed), 575.2784 (Calculated)
Structure confirmed by 1H-NMR
Electronic Absorption Spectra
Wavelength (nm)
Ab
sorb
an
ce (
No
rm.)
SQ-83 [653 nm]
SQ-84 [663 nm]
SQ-8 [636 nm]
300 400 500 600 7000
0.4
0.8
1.2
Wavelength (nm)
Ab
sorb
an
ce (
No
rm.)
SQ-8
SQ-83
400 500 600 7000
0.5
1
SQ-Dyes in Ethanol Solution SQ-Dyes adsorbed on TiO2
SQ-8 SQ-84 SQ-83
Photovoltaic Characteristics
Cu
rren
t d
ensi
ty (
mA
/cm
2)
Voltage (V)
COOH
Cyanoacrylate
Thiophene-cyanoacrylate
0 0.1 0.2 0.3 0.4 0.5 0.6
2
4
6
8
10
12
Dyes Jsc (mA/cm2) Voc (V) FF Efficiency
SQ-8 6.71 0.58 0.72 2.82 %
SQ-83 11.53 0.63 0.69 5.03 %
SQ-84 6.93 0.58 0.66 2.67 %
Photovoltaic Parameters
Photocurrent Action Spectra
IPC
E
Wavelength (nm)
COOH
Cyanoacrylate
Thiophene-Cyanoacrylate
300 400 500 600 700 8000
0.1
0.2
0.3
0.4
0.5
0.6
0.7
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.
Conclusions: