Supporting Information for
Isoindigo-Based Small Molecules for Solution-Processed Organic
Photovoltaic Devices: Electron Donating Effect of Donor Group
on Photo-Physical Properties and Device Performance
Walaa Elsawy
1,2,7, Chang-Lyoul Lee
3,*, Shinuk Cho
4, Seung-Hwan Oh
5, Seung-Hyeon
Moon,6
Ahmed Elbarbary 7
and Jae-Suk Lee1,2,
*
1Department of Nanobio Materials and Electronics and School of Material Science and Engineering, 2Research Institute for
Solar and Sustainable Energies (RISE), 3Advanced Photonics Research Institute (APRI), 6School of Environmental Science
and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 500-712, Republic of Korea 4Departments of Physics and EHSRC, University of Ulsan, Ulsan 680-749, Republic of Korea 5Radiation Research Division for Industry & Environment, Korea Atomic Energy Research Institute (KAERI), 580-185,
Republic of Korea 7 Department of Chemistry, Faculty of Science, Tanta University, Tanta 31527, Egypt
Electronic Supplementary Material (ESI) for Physical Chemistry Chemical PhysicsThis journal is © The Owner Societies 2013
Fig. S1 PL spectra of isoindigo donor-acceptor-donor (D-A-D) small molecules in solution
state. The chloroform was used as solvent. The solution concentration was 10-5
mol.
Fig. S2 Thermo Gravimetric Analysis (TGA) curves of isoindigo donor-acceptor-donor (D-
A-D) small molecules.
500 600 700 800 900 1000
IDED
IDHT
IDT
ID2T
ID3TP
L i
ne
nis
ty (
a.u
.)
Wavelength (nm)
100 200 300 400 500 6000
20
40
60
80
100
Weig
ht
(%)
Temperature (oC)
IDED
IDHT
IDT
ID2T
ID3T
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Fig. S3 (a) Current density versus voltage characteristics of ITO/PEDOT:PSS/
ID2T:PC70BM/TiO2/Al organic photovoltaic devices with different donor and acceptor ratio
without DIO. (b) Current density versus voltage characteristics of ITO/PEDOT:PSS/
ID2T:PC70BM(70:30)/TiO2/Al organic photovoltaic devices with different DIO content.
-0.2 0.0 0.2 0.4 0.6 0.8 1.0-8
-6
-4
-2
0
2
4
Cu
rren
t d
en
sit
y (
mA
/cm
2)
Voltage (V)
ID2T:PC70
BM (50:50)
ID2T:PC70
BM (60:40)
ID2T:PC70
BM (70:30)
ID2T:PC70
BM (80:20)
(a)
-0.2 0.0 0.2 0.4 0.6 0.8 1.0-8
-6
-4
-2
0
2
4
Cu
rre
nt
de
ns
ity
(m
A/c
m2)
Voltage (V)
ID2T:PC70
BM (0.05% DIO)
ID2T:PC70
BM (0.1% DIO)
ID2T:PC70
BM (0.15% DIO)
ID2T:PC70
BM (0.2% DIO)
(b)
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Table S1 Photovoltaic performance of ITO/PEDOT:PSS/ID2T:PC70BM/TiO2/Al organic
photovoltaic devices with different donor and acceptor ratio (without DIO) and DIO content.
The ID2T and PC70BM ratio was fixed with 70:30 in photovoltaic devices with different DIO
content.
Donor : acceptor ratio Jsc(mA/cm2) Voc(V) FF (%) PCE (%)
50:50 4.42 0.92 29.1 1.19
60:40 6.12 0.93 35.4 2.04
70:30 7.0 0.93 36.3 2.30
80:20 4.86 0.88 34.8 1.49
DIO content (%)
0.05 5.93 0.85 31.7 1.59
0.1 6.58 0.93 42.8 2.60
0.15 5.48 0.93 44.6 2.26
0.2 2.77 0.80 40.9 0.90
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Fig. S4 (a) Current density versus voltage characteristics of ITO/PEDOT:PSS/IDHT:
PC70BM (70:30)/TiO2/Al and ITO/PEDOT:PSS/IDED:PC70BM (70:30)/TiO2/Al organic
photovoltaic devices with 0.1% DIO.
-0.2 0.0 0.2 0.4 0.6 0.8-0.4
-0.2
0.0
0.2
0.4
0.6
IDED:PC70
BM
IDHT:PC70
BM
C
urre
nt
de
ns
ity
(m
A/c
m2)
Voltage (V)
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Fig. S5 Output and transfer characteristics of OTFTs based on the isoindigo donor-acceptor-
donor (D-A-D) small molecules. (a) IDED, (b) IDHT, (c) IDT, (d) ID2T and (e) ID3T.
(a)
-60 -40 -20 0 20
10-12
10-11
10-10
10-9
10-8
Vds
=-60V
| I d
s | (
A)
Vgs
(V)-60 -40 -20 0
-10
-8
-6
-4
-2
0
Id
s (
nA
)
Vds
(V)
-60 -40 -20 0 200.00
0.02
0.04
0.06
0.08
0.10
0.12
Vt=-20V
(| I
ds |)1
/2 (
x10
-3 A
1/2)
Vgs
(V)
(b)
-60 -40 -20 0-0.20
-0.15
-0.10
-0.05
0.00
Id
s (A
)
Vds
(V)-60 -40 -20 0 20
0.0
0.1
0.2
0.3
0.4
0.5
0.6
V
t=-21V
(| I
ds |)1
/2 (
x10
-3 A
1/2)
Vgs
(V)-60 -40 -20 0 20
10-12
10-11
10-10
10-9
10-8
10-7
10-6
Vds
=-60V
| I d
s | (
A)
Vgs
(V)
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(c)
-60 -40 -20 0-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0.0
Id
s (A
)
Vds
(V)-60 -40 -20 0 20
0.0
0.5
1.0
1.5
2.0
2.5
Vt=-18V
(| I
ds |)1
/2 (
x10
-3 A
1/2)
Vgs
(V)-60 -40 -20 0 20
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
Vds
=-60V
| I d
s | (
A)
Vgs
(V)
(d)
-60 -40 -20 0-10
-8
-6
-4
-2
0
Id
s (A
)
Vds
(V)-60 -40 -20 0 200
1
2
3
4
Vt=-16V
(| I
ds |)1
/2 (
x10
-3 A
1/2)
Vgs
(V)-60 -40 -20 0 20
10-12
10-11
10-10
10-9
10-8
10-7
10-6
10-5
| I d
s | (
A)
Vgs
(V)
Vds
=-60V
(e)
-60 -40 -20 0-0.14
-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
Id
s (A
)
Vds
(V)-60 -40 -20 0 20
10-12
10-11
10-10
10-9
10-8
10-7
10-6
| I d
s | (
A)
Vgs
(V)
Vds
=-60V
-60 -40 -20 0 20
0.0
0.1
0.2
0.3
0.4
0.5
(| I
ds |)1
/2 (
x10
-3 A
1/2)
Vgs
(V)
Vt=-26V
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Table S2 Field-effect charge transport properties of isoindigo donor-acceptor-donor (D-A-D)
small molecules. Vds is -60V.
Active layer h(cm2/(Vs)) Ion/Ioff Vt (V)
IDED 3.2 10-5
4.5 103 -20
IDHT 1.1 10-3
5.7 104 -21
IDT 1.4 10-2
1.3 106 -18
ID2T 3.6 10-2
3.4 106 -16
ID3T 9.7 10-4
1.0 105 -26
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Fig. S6 Transfer curves of OTFTs based on the isoindigo donor-acceptor-donor (D-A-D)
small molecules:PC70BM (70:30) film. (a) IDT (b) IDHT and IDED.
(a)
-60 -40 -20 0 20 40 60
10-9
10-8
10-7
10-6
p-type operation
Vds
= -60 V
n-type operation
Vds
= 60 VIDT:PC
71BM
| I d
s | (
A)
Vgs
(V)
w/o DIO
w/ DIO
w/o DIO
w/ DIO
(b)
-60 -40 -20 0 20 40 6010
-11
10-10
10-9
10-8
n-type operation
Vds
= 60 V
p-type operation
Vds
= -60 V
| I d
s | (
A)
Vgs
(V)
IDED
IDHT
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Table S3 Field-effect charge transport properties of isoindigo donor-acceptor-donor (D-A-D)
small molecules:PC70BM (70:30). Vds is 60V.
Active layer e(cm2/(Vs))
a h(cm
2/(Vs))
a e(cm
2/(Vs))
b h(cm
2/(Vs))
b
IDED:PC70BM 4.62 10-5
2.09 10-5
N/Ac N/A
c
IDHT:PC70BM 5.19 10-5
2.96 10-5
N/Ac N/A
c
IDT:PC70BM 6.15 10-3
1.37 10-4
7.80 10-3
8.76 10-3
aElectron and hole mobility of photo-active layer without DIO,
bElectron and hole mobility of
active photo-layer with 0.1% DIO, cNot available, there was no additive effect on the
IDED:PC70BM and IDHT:PC70BM films.
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Fig. S7
1H and
13C NMR spectrum of 6, 6’-dihydrothieno[3,4-b][1,4]dioxin-2-yl-N,N’-(2-
ethylhexyl)-isoindigo (IDED) in CDCl3.
N
N
O
OS
S
N
NO
OS
S
OO
O O
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Fig. S8 1H and
13C NMR spectrum of 6,6’-dihexylthiophen-2-yl-N,N’-(2-ethylhexyl)-
isoindigo (IDHT) in CDCl3.
Fig. S9 1H and
13C NMR of spectrum of 6, 6’-thiophen-2-yl-N,N’-(2-ethylhexyl)-isoindigo
(IDT) in CDCl3.
Fig. S10
1H and
13C NMR spectrum of 6, 6’-bithiophen-2-yl-N,N’-(2-ethylhexyl)-isoindigo
(ID2T) in CDCl3.
N
NO
OS
S
N
NO
OS
S
S
S
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Fig. S11
1H and
13C NMR spectrum of 6, 6’-terthiophen-2-yl-N,N’-(2-ethylhexyl)-isoindigo
(ID3T) in CDCl3.
N
NO
OS
S
S
S
S
S
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