Supplementary Information
Multi-layering of a Nanopatterned TiO2 Layer for Highly
Efficient Solid-State Solar Cells
Jongbeom Na, Younghoon Kim, Chihyun Park and Eunkyoung Kim*
Active Polymer Center for Pattern Integration, Department of Chemical and Biomolecular
Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea
E-mail: eunkim@yonsei.kr
Homepage: http://web.yonsei.ac.kr/eunkim
Keywords: multi-layered, nanopatterned TiO2, light harvesting, solid-state solar cells,
photoanode.
1
Supplementary Figure S1. SEM image of multi-layered nanopatterned photoanodes (MNPs)
with top view; (a) 2-layered nanopatterned photoanode (2NP) (scale bar: 2 μm), (b) 3-layered
nanopatterned photoanode (3NP) (scale bar: 5 μm), (c) 4-layered nanopatterned photoanode
(4NP) (scale bar: 7 μm). Cross view of MNPs at the (d) nanopatterned TiO2 layer (scale bar:
300 nm), (e) nanopattern interface (scale bar: 500 nm) and f) magnified image of e) (scale bar:
100 nm).
Supplementary Figure S2. SEM image of nanopatterned TiO2 layer with top view; (a)
before spin-coating polystyrene (PS) solution, (b) after spin-coating PS of 0.1 wt% solution,
(c) 0.5 wt%, (d) 1 wt%, (e) 3 wt% and (f) 5 wt%. (scale bar: 200 nm)
Supplementary Figure S3. The Fourier transform infrared spectroscopy (FT-IR) of
polystyrene (PS) and MNPs. Commercially available PS (black line), MNPs after spin-coating
PS (red line) and MNPs after calcination. (blue line)
Supplementary Figure S4. The EDS analysis of nanopatterned TiO2 layer. (a, b, c) The SEM
image and (b, d, f) EDS mapping image of nanopatterned TiO2 layer (a,b) before spin-coating
polystyrene (PS) solution, (c, d) after spin-coating PS solution (5 wt%), and (e, f) after
calcination at 500 °C for 30 min. The element color (Ti: green, O: blue, C: red) (scale bar: 1
μm).
Supplementary Figure S5. The light transmittance characteristic of MNPs after N719 dye
loading. Flat (black), 1NP (red), 2NP (blue), 3NP (magenta), and 4NP (green).
Supplementary Figure S6. The absorption spectra of desorbed N719 dye from the MNPs in
a solution of NaOH (5 mM) in an ethanol/water (1:1 v/v) mixture. Flat (black), 1NP (red),
2NP (blue), 3NP (magenta), and 4NP (green).
Supplementary Figure S7. (a) The electron lifetime (τr), (b) diffusion coefficient (Dn), and (c)
diffusion length (Ln) of the ssDSSCs fabricated with multi-nanopatterned photoanodes (MNPs)
as determined from the IMPS / IMVS measurement. Flat (black), 1NP (red), 2NP (blue), 3NP
(magenta), and 4NP (green).
2
Supplementary Table S1. The atomic percent of elements in the MNPs by EDS analysis.
a)
Sample
Atomic percent
(%) of titanium
(Ti)
Atomic percent
(%) of oxygen
(O)
Atomic percent
(%) of carbon
(C)
Total atomic
percent (%)
Before PS coating
33.3
66.7
-
100
After PS coating a)
7.2
4.6
88.2
100
After calcination
(500°C, 30 min)
33.1
66.9
-
100
The 5 wt% of PS solution was spin-coated on the nanopatterned TiO2 film.
Supplementary Table S2. Relative absorption, transmittance and reflectance data of different
number of nanopatterned layer of MNPs.
Relative
Relative
Relative
absorption b)
transmittance b)
reflectance b)
(400 nm ~ 700 nm)
(400 nm ~ 700 nm)
(400 nm ~ 700 nm)
Flat
1
1
1
1NP
1.16
0.81
1.29
2NP
1.24
0.65
1.37
3NP
1.26
0.57
1.43
4NP
1.27
0.53
1.51
Sample a)
a)
Relative absorption, transmittance and reflectance of samples were calculated by integrating
UV-vis spectrum. b) Relative optical data with reference to the absorption of flat, characterized
by UV-vis spectroscopy.
3
Supplementary Table S3. The weight percent of TiO2 paste for fabricating MNPs and
amount of dye loading of MNPs.
Weight percent of TiO2 paste b)
Dye loading c)
(wt %)
(nmol cm-2)
Flat
100
86.1
1NP
100
85.7
2NP
80
85.5
3NP
65
85.9
4NP
50
85.4
Sample a)
The thickness of MNPs was 12 μm. b) The TiO2 paste were diluted by organic solvent (terpineol) with
vigorous stirring. c) The concentration of desorbed dye solution was analyzed by using a UV/Vis
spectrophotometer.
a)
4