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Supporting Information

Over 10% Efficiency in Single-Junction Polymer Solar Cells Developed

from Easily Accessible Random Terpolymers

Hye Jin Cho a,1, Yu Jin Kim b,1, Shanshan Chen a,, Jungho Lee a,, Tae Joo Shin c,*, Chan Eon Park b,* , Changduk Yang a,*

aDepartment of Energy Engineering, School of Energy and Chemical Engineering, Low Dimensional Carbon Materials Center, Perovtronics Research Center, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulju-gun, Ulsan 44919, Republic of Korea. bPOSTECH Organic Electronics Laboratory, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Republic of KoreacUNIST Central Research Facilities & School of Natural Science, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, Republic of KoreaE-mail: [email protected], [email protected], [email protected]

Keywords: Conjugated Polymer, Power Conversion Efficiency, Polymer Solar Cell, Random

Terpolymer, Single-junction Solar Cell

General measurements and materialsS1

Instrumentations for film morphology

Premium silicon cantilevers (TESP-V2) were used with a rotated tip to provide more

symmetric representation of features over 200 nm. The bulk morphology images were

acquired on a JEM-2100F high-resolution transmission electron microscope (HR-TEM) at

200 kV accelerating voltage. The TEM samples were spin-casted on top of ITO/PEDOT:PSS

substrates. After that, substrates were transferred to deionized water and the floated films were

transferred to TEM grids (200 mesh copper grids). The peeled-off film deposited on TEM

grids was dried overnight in a vacuum oven.

Transient photovoltage spectroscopy

Transient photovoltage (TPV) experiments were performed on a HuaMing measurement

system (201501 model) by connecting the devices to a high input impedance oscilloscope (1

MΩ) which allows measuring Voc under variation of a white light illumination. TPV

spectroscopy was measured at zero current conditions by applying a bias which equals Voc at

varying continuous irradiation conditions. The average lifetime of photo-induced charges

could approximately be estimated by fitting a decay of the open-circuit potential transient

with exp (−t τ c❑−1), where t is the time and τ c is an average time constant before

recombination.

Typical procedure for Stille polymerization. The monomers TPTI-Br2 (80 mg, 0.0859

mmol), T, and 2T were mixed in 12 mL of anhydrous toluene. After degassing under argon

for 10 min, Pd2(dba)3 (2.359 mg, 2.57 µmol) and P(o-tolyl)3 (3.13 mg, 10.28 µmol) were

added as the catalyst and ligand. The reaction mixture was stirred at 100 oC for 3 days under

argon. Then, 2-(tributylstannyl)thiophene and 2-bromothiophene were added to end-cap the

polymer chain. The reaction mixture was cooled to room temperature and precipitated into

methanol. The precipitate was purified by Soxhlet extraction in the sequences of methanol, S2

acetone, hexane, and chloroform. The chloroform fraction was re-precipitated using methanol

and dried. Finally, PTPTI-T series terpolymers were obtained as a dark purple solid.

PTPTI-T100: Isolated yield = 82.3% (60.3 mg). GPC (TCB, 120 °C, against PS standard) Mn

= 95.3 kDa, Mw = 143.5 kDa, and PDI = 1.50; 1H NMR (400 MHz, CDCl3, δ): 8.6-7.71(br,

Ar–H), 6.84-6.00 (br, Ar–H), 5.25-4.5 (br, N–CH2), 1.56-1.00 (m, br, –CH, –CH3), 0.97-0.4

(m, br, –CH3). Anal. calcd for C52H72N2O2S3: C 73.19, H 8.50, N 3.28, O 3.75 S 11.27; found:

C 73.17, H 8.29, N 3.01, S 11.10.

PTPTI-T70: Isolated yield = 95.9 % (72.3 mg). GPC (TCB, 120 °C, against PS standard) Mn



(m, br, –CH3). Anal. calcd for [(C52H72N2O2S3)0.7 + (C56H74N2O2S4)0.3]: C 72.80, H 8.34, N

3.19, S 12.00; found: C 72.12, H 8.30, N 2.68, S 11.50.

PTPTI-T50: Isolated yield = 90.6 % (69.7 mg). GPC (TCB, 120 °C, against PS standard) Mn



(m, br, –CH3). Anal. calcd for [(C52H72N2O2S3)0.5 + (C56H74N2O2S4)0.5]: C 72.54, H 8.23, N

3.13, S 12.49; found: C 72.03, H 8.24, N 2.66, S 12.34.

PTPTI-T30: Isolated yield = 81 % (63.4 mg). GPC (TCB, 120 °C, against PS standard) Mn =

84.1 kDa, Mw = 172.2 kDa, and PDI = 2.04; 1H NMR (CDCl3, 400 MHz): δ (ppm) 8.6-

7.71(br, Ar–H), 6.84-6.00 (br, Ar–H), 5.25-4.5 (br, N–CH2), 1.56-1.00 (m, br, –CH, –CH3),

0.97-0.4 (m, br, –CH3). Anal. calcd for [(C52H72N2O2S3)0.3 + (C56H74N2O2S4)0.7]: C 72.28, H

8.12, N 3.07, S 12.97; found: C 71.88, H 7.85, N 2.60, S 12.88.

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Figure S1. 1H-NMR spectra of four TPTI-T based polymers in CDCl3. The broad peaks in the range of 1.56-1.00 are assigned to methylene protons (-CH2-R, methylene) of the hexyldecyl side chain groups.

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Figure S2. DSC thermograms of the TPTI-T based polymers with a heating rate of 5 ºC min -1 under N2. (dark cyan:PTPTI-T100, pink:PTPTI-T70, dark yellow:PTPTI-T50, and purple:PTPTI-T30, respectively)

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Figure S3. UV-vis absorption spectra of the TPTI-T based polymers in solution (1×10-5 M in chloroform).

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Figure S4. Cyclic voltammograms of TPTI-T based polymers with onset points drawn by black lines highlighted for reduction and oxidation, respectively (measurement with a three-electrode cell in a 0.1 M tetra-n-butylammonium hexafluorophosphate (n-Bu4NPF6) solution in acetonitrile at a scan rate of 100 mV/s at room temperature under argon).

PTPTI-T100 and PTPTI-2T

PTPTI-T70

S8

PTPTI-T50

PTPTI-T30

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Figure S5. Optimized frontier molecular geometries, simulated HOMO (bottom) and LUMO (top) orbitals for the TPTI-T based polymers with trimer or tetramer oligomers depending on the ratios and random sequences of T and 2T chromophores in the backbone (1:0, 0:1, 2:1, 1:1 and 1:2, respectively).

Figure S6. PTPTI-T100 with low molecular weight (L-Mw) polymer solar cell (PSC) performance: J-Vcurves (a) and EQE results (b)

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Figure S7. EQE spectra for each device and the integrated photocurrent density (shown on the right axis)

Figure S8. Additional PSCs data. J-V curves (a) and EQE results (b) of representative PTPTI-T70:PC71BM BHJ solar cell systems with different cathode layers.

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Table S1. Photovoltaic performance parameters of optimized PTPTI-T70:PC71BM BHJ solar cell with different cathode layer.

Active layer CathodeVoc

(V)Jsc(mA / cm2)

FF(%)

PCEbest (%)

PCEavg* (%)

PTPTI-T70:PC71BM

Al 0.78 14.3 61.2 6.82 6.33

LiF/Al 0.81 17.5 67.4 9.55 8.97

PFN/Al 0.83 18.1 70.5 10.59 9.52

*The average PCE values were obtained from more than 16 separate devices.

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Figure S9. (a) J-V curves of copolymer:PC71BM inverted solar cells with device structure ITO/ZnO/copolymer:PC71BM/MoO3/Ag and (b) their corresponding EQE curves.

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Table S2. Device performance parameters for TPTI-T-based inverted polymer solar cells in blends with PC71BM under the optimized conditions.

Active layer Voc (V)

Jsc(mA / cm2)

FF (%)

PCEbest (%)

PCEavg* (%)

PTPTI-T100 0.80 11.4 51.2 4.72 3.96

PTPTI-T70 0.81 18.7 60.1 9.10 8.41

PTPTI-T50 0.82 20.7 59.3 10.29 7.93

PTPTI-T30 0.81 15.4 48.4 6.03 5.22*The average PCE values were obtained from more than 16 separate devices.

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Figure S10. Morphology characterizations of the blend films. Two-dimensional (2D) AFM phase images (upper line). TEM images (lower line) of TPTI-T based polymer:PC71BM blend films for the optimal polymer solar cell fabrication (a and e = PTPTI-T100:PC71BM, b and f = PTPTI-T70:PC71BM. c and g = PTPTI-T50:PC71BM, and d and h = PTPTI-T30:PC71BM, where inner scale bar is 1 µm).

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PTPTI-T100 PTPTI-T70

PTPTI-T50 PTPTI-T30

Figure S11. Close-up TEM images for TPTI-based polymer:PCBM blends. Yellow dash lines show approximate domain size – PTPTI-T100 (14 nm), PTPTI-T70 (22 nm), PTPTI-T50 (16 nm), and PTPTI-T30 (27 nm).

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Figure S12. In- and out-of-plane 1D GIWAXD profiles of the neat polymer and polymer:PC71BM blend films.

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Figure S13. 2D-GIWAXD images of the polymer:PC71BM blend films measured below the critical angle of films (αi = 0.11° < αc). a, PTPTI-T100:PC71BM, b, PTPTI-T70:PC71BM, c, PTPTI-T50:PC71BM, and d, PTPTI-T30:PC71BM blend films, respectively.

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Figure S14. Pole figures of azimuthal-cuts along the (010) - stacking peaks in the polymer:PC71BM blend films both in surface (αi = 0.11° < critical angle) and bulk (αi = 0.12° > critical angle) region of the films. a, PTPTI-T100:PC71BM b, PTPTI-T70:PC71BM c, PTPTI-T50:PC71BM, and d, PTPTI-T30:PC71BM blend films, respectively. The stronger intensity appeared at 90o

(and 0o and 180o) in the pole figures represents orientation of (010) - stacking is mainly parallel (and perpendicular) to the substrate.

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Figure S15. Relative percentages of the (010) - stacking orientations parallel to the substrate in blend films. The percentage of the - stacking orientation parallel to the substrate was calculated from the integrated intensity of the azimuthal angle (χ) of 45-135o. The surface data were extracted from the incident angle, αi = 0.11° and bulk data from αi = 0.12°.

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Table S3. Crystallographic parameters of 2D-GIWAXD measurements for TPTI-T based neat polymer films.

condition TPTI-T based neat polymer filmsa

polymer b T100 T70 T50 T30

Out-of-

plane

(100)

qz (Å -1)pristine

0.2910 0.3004 0.3004 0.3120

d-spacing (Å) 21.6 20.9 20.9 20.1

Out-of-

plane

(010)

qz (Å -1)

pristine

1.7270 1.7350 - -

d-spacing (Å) 3.6 3.6 - -

FWHM (Å-1)c 0.2530 0.2450 - -

Coherence

length (Å)22.6 23.4 - -

In-plane

(100)

qxy (Å -1)Pristine

0.2900 0.2876 0.2960 0.2730

d-spacing (Å) 21.7 21.8 21.3 23.0

In-plane

(010)

qxy (Å -1)

Pristine

- 1.7560 1.7520 1.7550

d-spacing (Å) - 3.6 3.6 3.6

FWHM (Å -1)c - 0.1753 0.1850 0.1800

Coherence

length (Å)- 32.7 37.6 31.8

ameasured at the bulk region of the films (incident angle, αi = 0.12° > critical angle).bT100 = PTPTI-T100, T70 = PTPTI-T70, T50 = PTPTI-T50 and T30 = PTPTI-T30 based neat films, respectively. cFWHM = full-width at half maximum.

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Table S4. Crystallographic parameters of 2D-GIWAXD measurements for TPTI-T based polymer:PC71BM blend films.

condition TPTI-T based polymer:PC71BM blend filmsa

polymer b T100 T70 T50 T30

Out-of-

plane

(100)

qz (Å -1)pristine

0.2928 0.2984 0.3079 0.3040

d-spacing (Å) 21.5 21.1 20.4 20.7

Out-of-

plane

(010)

qz (Å -1)

pristine

1.7304 1.7336 - -

d-spacing (Å) 3.6 3.6 - -

FWHM (Å -1)c 0.1867 0.2216 - -

Coherence

length (Å)30.3 25.5 - -

In-plane

(100)

qxy (Å -1)Pristine

0.2763 0.2819 0.2858 0.2837

d-spacing (Å) 22.7 22.3 22.0 22.1

In-plane

(010)

qxy (Å -1)

Pristine

- 1.7606 1.7239 1.7286

d-spacing (Å) - 3.6 3.6 3.6

FWHM (Å -1)c - 0.3265 0.3020 0.2914

Coherence

length (Å)- 17.3 18.7 19.4

aMeasured at the bulk region of the films (incident angle, αi = 0.12° > critical angle)bT100 = PTPTI-T100, T70 = PTPTI-T70, T50 = PTPTI-T50 and T30 = PTPTI-T30 based blend films, respectively. cFWHM = full-width half maximum.

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Figure S16. Hole and electron mobilities of TPTI-T based polymer:PC71BM blend films by a SCLC method. Dark J1/2-V plots for the hole- (a) and electron- (b) only devices based on TPTI-T based polymer:PC71BM blend films cast under the same conditions for the optimal solar cell performance.

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1.00 1.25 1.50 1.75

qxy (Å-1

)

Inte

nsity

(a.u

.) / i

n-pl

ane

PTPTI-T100:PC71BM PTPTI-T70:PC71BM PTPTI-T50:PC71BM PTPTI-T30:PC71BM

Figure S17. 1D profiles extracted from 2D-GIWAXS patterns at the scattered range of 1.0 – 1.75 Å-1 for four blend films.

Figure S18. Life time dependence of TPTI-T based PSCs. Transient photovoltage decay profiles from different four TPTI-T based heterojunction polymer solar cells.

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