SUPPORTING INFORMATION
(a)
1.2
Absorbance
1
0.8
1
0.6
2
0.4
3
0.2
0
4000
3500
3000
-1
Wavenumber / cm
2500
(b)
1
Absorbance
0.8
1
0.6
2
0.4
0.2
0
4000
3
3500
3000
-1
Wavenumber / cm
2500
Figure S1. FTIR spectra (4000−2500 cm−1) of (a) the untreated films, (1) F-1NF, (2) F-2NF,
and (3) F-3NF, and (b) those steam-treated for 120 min, (1) F-1NF-s, (2) F-2NF-s, and (3)
F-3NF-s.
(a)
0.8
Absorbance
0.6
1
0.4
2
0.2
3
0
400
450
500
550
600
Wavelength / nm
(b)
Absorbance
0.2
1
0.1
2
3
0
400
450
500
550
600
Wavelength / nm
Figure S2. Visible absorption spectra and the separated constituent spectra of (a) the untreated
films, (1) F-1NF, (2) F-2NF, and (3) F-3NF, and (b) those steam-treated for 120 min, (1)
F-1NF-s, (2) F-2NF-s, and (3) F-3NF-s.
(a)
Emission intensity
10000
1
2
3
1000
100
10
1
0
2
4
6
8
10
Time / ns
(b)
Emission intensity
10000
1
2
3
1000
100
10
1
0
2
4
6
8
10
Time / ns
Figure S3. Fluorescence decay profiles of (a) the untreated films, (1) F-1NF, (2) F-2NF, and
(3) F-3NF, and (b) those steam-treated for 120 min, (1) F-1NF-s, (2) F-2NF-s, and (3)
F-3NF-s.
A Ti:Sapphire femtosecond pulse laser and streak scope spectroscopic system were used for
the time-resolved fluorescence measurements in order to obtain information about the
fluorescence quenching due to the electron injection from the dye to the titania.
The laser
system (Clark MXR CPA 2001) generates laser pulses of 150 fs duration (FWHM) with an
energy of 750 μJ at 750 nm and a repetition rate of 1 kHz.
laser pulses (375 nm) was used for the excitation.
The second harmonics of the
The fluorescence signal was monitored
using a streak scope system (Hamamatsu Photonics C4780).
The fluorescence decay
curves were obtained by integrating the fluorescence signals in the 500–550 nm region.
The film samples for this measurement were washed with a 0.1 mol dm3 sodium hydroxide
aqueous solution and water in order to adjust to the same amount of the dye.
of the dye was confirmed by a UV-visible absorption measurement.
The amount
Table S1. Emission intensity and fitting parameters of the time-resolved fluorescence of (a)
the untreated films, (1) F-1NF, (2) F-2NF, and (3) F-3NF, and (b) those steam-treated for 120
min, (1) F-1NF-s, (2) F-2NF-s, and (3) F-3NF-s.
Maximum
intensity
τ1 / ns
τ2 / ns
A1
A2
F-1NF
2030±70
0.40±0.01
3.7±0.1
0.96±0.01
0.04±0.01
F-2NF
2320±60
0.42±0.01
3.5±0.1
0.95±0.01
0.05±0.01
F-3NF
2540±50
0.43±0.01
3.5±0.1
0.90±0.02
0.10±0.02
F-1NF-s
950±40
0.20±0.01
3.3±0.1
0.98±0.01
0.02±0.01
F-2NF-s
1360±50
0.24±0.01
3.3±0.1
0.97±0.01
0.03±0.01
F-3NF-s
2150±80
0.25±0.01
3.4±0.1
0.96±0.01
0.04±0.01
(a)
100 nm
(b)
100 nm
Figure S4. SEM images of the surface morphology of the electrodes steam-treated for 120
min, (a) WE-2HF-s and (b) WE-2SF-s.
Intensity (arb. units)
20
1
2
3
25
30
35
40
45
50
2θ / degree
Figure S5. XRD patterns of the films steam-treated for 120 min, (2) F-2NF-s, (3) F-2HF-s,
and (4) F-2SF-s.
(a)
0.7
Absorbance
0.6
1
0.5
0.4
2
0.3
3
0.2
0.1
0
1800
1600
1400
Wavenumber / cm-1
1200
1000
(b)
Absorbance
0.8
1
0.6
2
0.4
3
0.2
0
1800
1600
1400
Wavenumber / cm-1
1200
1000
Figure S6. FTIR spectra (1800−1000 cm−1) of (a) the untreated films, (1) F-2NF, (2) F-2HF,
and (3) F-2SF, and (b) those steam-treated for 120 min, (1) F-2NF-s, (2) F-2HF-s, and (3)
F-2SF-s.
(a)
1
Absorbance
0.8
1
0.6
2
0.4
0.2
0
4000
3
3500
3000
-1
Wavenumber / cm
2500
(b)
1
Absorbance
0.8
1
0.6
0.4
2
0.2
3
0
4000
3500
3000
-1
Wavenumber / cm
2500
Figure S7. FTIR spectra (4000−2500 cm−1) of (a) the untreated films, (1) F-2NF, (2) F-2HF,
and (3) F-2SF, and (b) those steam-treated for 120 min, (1) F-2NF-s, (2) F-2HF-s, and (3)
F-2SF-s.
(a)
0.8
Absorbance
0.6
1
0.4
2
0.2
3
0
400
450
500
550
600
Wavelength / nm
(b)
0.4
1
Absorbance
0.3
0.2
0.1
2
3
0
400
450
500
550
600
Wavelength / nm
Figure S8. Visible absorption spectra and the separated constituent spectra of (a) the untreated
films, (1) F-2NF, (2) F-2HF, and (3) F-2SF, and (b) those steam-treated for 120 min, (1)
F-2NF-s, (2) F-2HF-s, and (3) F-2SF-s.
Table S2. Concentrations (/ mol dm−3) of the neutral, anion, and dianion species of
fluorescein in the untreated films, F-2NF, F-2HF, and F-2SF, and those steam-treated for 120
min, F-2NF-s, F-2HF-s, and F-2SF-s.
Neutral
Anion
Dianion
Total
F-2NF
0.131 (26.1%)
0.364 (72.5%)
0.00705 (1.4%)
0.502
F-2HF
0.00986 (21.5%) 0.352 (76.8%)
0.00778 (1.7%)
0.459
F-2SF
0.141 (29.6%)
0.332 (69.5%)
0.00474 (1.0%)
0.479
F-2NF-s
0.00648 (27.5%) 0.164 (69.5%)
0.00717 (3.0%)
0.236
F-2HF-s
0.109 (26.2%)
0.00633 (1.5%)
0.416
F-2SF-s
0.00527 (21.6%) 0.0187(76.7%)
0.301 (72.3%)
0.000420 (1.7%) 0.0244
(a)
30
Intensity
3
20
2
1
10
0
500
550
600
650
700
650
700
Wavelength / nm
(b)
10
2
Intensity
8
6
1
4
3
2
0
500
550
600
Wavelength / nm
Figure S9. Fluorescence spectra of (a) the untreated films, (1) F-2NF, (2) F-2HF, and (3)
F-2SF, and (b) those steam-treated for 120 min, (1) F-2NF-s, (2) F-2HF-s, and (3) F-2SF-s.
The excitation wavelength was 500 nm.
(a)
8
0.3
1
1
2
3
4
IPCE / %
IPCE / %
6
0.2
2
0.1
2
3
0
0
300
320
340
360
380
400
400
450
Wavelength / nm
500
550
Wavelength / nm
600
(b)
8
1
1
1
2
3
4
IPCE / %
IPCE / %
6
0.5
2
2
3
0
0
300
320
340
360
Wavelength / nm
380
400
400
450
500
550
Wavelength / nm
600
Figure S10. IPCE spectra of (a) the untreated electrodes, (1) WE-2NF, (2) WE-2HF, and (3)
WE-2SF, and (b) those steam-treated for 120 min, (1) WE-2NF-s, (2) WE-2HF-s, and (3)
WE-2SF-s.
Photocurrent density / μA cm-2
10
1
8
2
6
3
4
2
0
0
0.1
0.2
0.3
0.4
Voltage / V
Figure S11. I−V curves of the untreated electrodes, (1) WE-2NF, (2) WE-2HF, and (3)
WE-2SF.
The I−V curves of the electrodes were measured by a potentiostat (Hokuto Denko
HSV-100) during irradiation by the visible light at a wavelength longer than 400 nm emitted
by the 150-W Xe short arc lamp using a sharp cut filter.