Supporting Information

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1 Supporting Information Non-fullerene Acceptors with Enhanced Solubility and Ordered Packing for High- Efficiency Polymer Solar Cells Yahui Liu, a, Miao Li, a Xiaobo Zhou, b Qing-Qing Jia, c Shiyu Feng, a Pengcheng Jiang, a Xinjun Xu, a, * Wei Ma, b, * Hai-Bei Li, c Zhishan Bo a, * a Beijing Key Laboratory of Energy Conversion and Storage Materials, College of Chemistry, Beijing Normal University, Beijing , China. xuxj@bnu.edu.cn; zsbo@bnu.edu.cn b State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, Xi'an , China. msewma@mail.xjtu.edu.cn c School of Ocean, Shandong University, Weihai , China. lihaibei@sdu.edu.cn 1.1 Material and Instruments. Unless otherwise noted, all chemicals were purchased from Aldrich or Acros and used without further purification. The catalyst precursor Pd(PPh3)4 was prepared according to the literature and stored in a Schlenk tube under nitrogen atmosphere. Unless otherwise noted, all reactions were performed under an atmosphere of nitrogen and monitored by thin layer chromatography (TLC) on silica gel. Column chromatography was carried out on silica gel ( mesh). 1 H and 13 C NMR spectra were recorded on a Bruker AV 400 spectrometer. UV-visible absorption spectra were obtained on a PerkinElmer UV-vis spectrometer model Lambda 750. Elemental S1

2 analyses were performed on a Flash EA 1112 analyzer. Thermal gravimetric analysis (TGA) measurements were performed on TA2100 under a nitrogen atmosphere at a heating rate of 10 o C/min to record TGA curves. Atomic force microscopy (AFM) measurements were performed under ambient conditions using a Digital Instrument Multimode Nanoscope IIIA operating in the tapping mode. The thickness of the blend films was determined by a Dektak 6 M surface profilometer. The electrochemical behavior of the polymers was investigated using cyclic voltammetry (CHI 630A Electrochemical Analyzer) with a standard three-electrode electrochemical cell in a 0.1 M Bu4NPF6 solution in CH3CN at room temperature under an atmosphere of nitrogen with a scanning rate of 0.1 V/S. A Pt plate working electrode, a Pt wire counter electrode, and an Ag/AgNO3 (0.01 M in CH3CN) reference electrode were used. The experiments were calibrated with the standard ferrocene/ferrocenium (Fc) redox system and assumption that the energy level of Fc is 4.8 ev below vacuum. Grazing Incidence Wide-Angle X-ray Scattering (GIWAXS) Characterization: GIWAXS measurements were performed at beamline at the Advanced Light Source. Samples were prepared on Si substrates using identical blend solutions as those used in devices. The 10 kev X-ray beam was incident at a grazing angle of , selected to maximize the scattering intensity from the samples. The scattered x-rays were detected using a Dectris Pilatus 2M photon counting detector. Resonant Soft X-ray Scattering (RSoXS): RSoXS transmission measurements were performed at beamline at the Advanced Light Source (ALS). Samples for R- SoXS measurements were prepared on a PSS modified Si substrate under the same S2

3 conditions as those used for device fabrication, and then transferred by floating in water to a 1.5 mm 1.5 mm, 100 nm thick Si3N4 membrane supported by a 5 mm 5 mm, 200 μm thick Si frame (Norcada Inc.). 2-D scattering patterns were collected on an invacuum CCD camera (Princeton Instrument PI-MTE). The sample detector distance was calibrated from diffraction peaks of a triblock copolymer poly(isoprene-b-styreneb-2-vinyl pyridine), which has a known spacing of 391 Å. The beam size at the sample is approximately 100 μm by 200 μm. 1.2 Solar Cells Fabrication and Characterization PSCs were fabricated with the device configuration of ITO/ZnO/active layer (100 nm)/moo3 (85 Å)/Ag (100 nm). The conductivity of ITO is 20 Ω. A mixture of PBDB- T and acceptor molecule (IDTT2F and IDTOT2F) in 1,2-dichlorobenzene (DCB) was stirred at 110 o C at least two hours to ensure sufficient dissolution and then the blend solution was spin-coated onto ZnO layer to form active layer. On one substrate five cells with an effective area of 0.04 cm 2 for each were fabricated. Current-voltage characteristics were recorded using an Enli Technology Ltd., Taiwan (SS-F53A) under an AM 1.5G AAA class solar simulator with an intensity of 100 mw cm -2 as the white light source and the intensity was calibrated with a standard single crystal Si photovoltaic cell. The temperature while measuring the J-V curves was approximately 25 o C. The EQE measurements of PSCs were performed by the solar cell spectral response measurement system QE-R3011 (Enli Technology Ltd., Taiwan), which was calibrated by monocrystalline silicon solar cell in advance. S3

4 (a) Current (a.u.) IDTT2F IDTOT2F Potential ( V vs.ag/agcl) Absorption Coefficiency (10 5 cm -1 ) (b) IDTT2F IDTOT2F Wavelength (nm) Figure S1. a) CV curves and b) film absorption spectra of IDTT2F and IDTOT2F. Table S1. Energy levels of IDTT2F and IDTOT2F determined from CV measurements. HOMO (ev) LUMO (ev) IDTT2F IDTOT2F Figure S2. Chemical geometries of IDTT2F, IDTOT2F, and previously reported IEICO-4F determined by DFT calculations. S4

5 Figure S3. Energy levels of IDTT2F, IDTOT2F, and previously reported IEICO-4F determined via DFT calculations. Table S2. Photovoltaic performance of devices fabricated with PBDB-T and IDTT2F. Active layer Voc (V) Jsc (ma/cm 2 ) FF (%) PCE (%) PBDB-T:IDTT-2F=1: PBDB-T:IDTT-2F=1: PBDB-T:IDTT-2F=1: PBDB-T:IDTT-2F=1: S5

6 Table S3. Photovoltaic performance of devices fabricated with PBDB-T and IDTOT2F at a polymer concentration of 3.5 mg/ml with a spin-coating rate of 1200 r/min. Active layer Voc (V) Jsc (ma/cm 2 ) FF (%) PCE (%) PBDB-T:IDTOT2F=1: PBDB-T:IDTOT2F=1: PBDB-T:IDTOT2F=1: PBDB-T:IDTOT2F=1: Table S4. Photovoltaic performance of devices fabricated with PBDB-T and IDTOT2F with different additives. Active layer additive Voc (V) Jsc (ma/cm 2 ) FF (%) PCE (%) 0.1%DIO %DIO %DIO PBDB-T:IDTOT2F=1:1 0.5%DIO %DIO %DIO %CBA %CBA S6

7 0.7%CBA %CBA %1-CN %1-CN %1-CN %1-CN Table S5. Photovoltaic performance of devices fabricated with PBDB-T and IDTOT2F with different thermal annealing (TA) temperature for 5 min. PBDB-T:IDTOT-2F TA Voc (V) Jsc (ma/cm 2 ) FF (%) PCE (%) 1:1 100 o C :1 120 o C :1 140 o C :1 160 o C S7

8 Table S6. Photovoltaic performance of devices fabricated with PBDB-T and IDTOT2F at a polymer concentration of 4 mg/ml with different spin-coating rate. RPM Voc (V) Jsc (ma/cm 2 ) FF (%) PCE (%) Thickness (nm) Counts IDTT2F IDTOT2F PCE (%) Figure S4. The distribution of PCEs in each about 30 devices based on IDTT2F and IDTOT2F. Figure S5. Photographs illustrating the different solubilities of IDTT2F, IDTOT2F, and IEICO-4F in n-hexane solutions with the same solid content of 0.5 mg/ml. S8

9 T:IDTOT2F. (a) 80 (b) 70 J 1/2 A 1/2 m IDTT2F IDTOT2F J 1/2 A 1/2 m IDTT2F IDTOT2F V / V V / V Figure S7. J 1/2 V curves for determining hole (a) and electron (b) mobilities of IDTT2F- and IDTOT2F-based devices. Table S7. Hole and electron mobilities of devices with IDTT2F and IDTOT2F. Active layer µh (cm 2 V -1 s -1 ) µe (cm 2 V -1 s -1 ) µh/µe Thickness PBDB-T:IDTT2F PBDB-T:IDTOT2F Figure S6. RSoXS profiles of blend films of PBDB-T:IDTT2F and PBDB- Experimental Section Synthesis of IDTT2F. 5,5'-(4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2-b:5,6- b']dithiophene-2,7-diyl)bis(thiophene-2-carbaldehyde) (2) S9

10 A mixture of compound 1 (400 mg, 0.32 mmol), 5-bromothiophene-2-carbaldehyde (185 mg, 0.97 mmol) and toluene (20 ml) was carefully degassed before and after Pd(PPh3)4 (40 mg) was added. The mixture was stirred and refluxed under N2 atmosphere for 8 hours. After the reaction finished, the solvent was moved under reduced pressure. The residue was purified by chromatography on silica gel column eluting with petrol ether/dcm (2:1, v/v) to give product 2 (330 mg) as an orange solid in a yield of 91%. 1 H NMR (500 MHz, CDCl3) δ: 9.85 (s, 2H), 7.66 (d, J = 3.95 Hz, 2H), 7.24 (s, 2H), 7.19 (d, J = 8.25 Hz, 8H), 7.11 (d, J = 8.25 Hz, 8H), 2.59 (t, J = 7.75, 8H), (m, 8H), (m, 24H), (m, 12H). 13 C NMR (125 MHz, CDCl3) δ: , , , , , , , , , , , , , , , , , 63.14, 35.58, 31.95, 31.73, 29.72, 29.38, 29.16, 22.71, 22.61, ,2'-((2Z,2'Z)-((5,5'-(4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2- b:5,6-b']dithiophene-2,7-diyl)bis(thiophene-5,2-diyl))bis(methanylylidene))bis(5,6- difluoro-3-oxo-2,3-dihydro-1h-indene-2,1-diylidene))dimalononitrile (IDTT2F) A mixture of 2 (300 mg, 0.27 mmol), 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden- 1-ylidene)malononitrile (300 mg, 1.30 mmol), and CHCl3 (30 ml) was carefully degassed. Then, 0.5 ml pyridine was added. After been stirred at room temperature overnight, the solvent was moved under reduced pressure. The residue was purified by chromatography on silica gel eluting with petrol ether/dcm (1:1, v/v) to give IDTT2F (253 mg) as a dark purple solid in a yield of 61%. 1 H NMR (500 MHz, CDCl3) δ: 8.84 (s,2h), 8.56 (dd, J = 6.50 Hz, J = 9.85 Hz, 2H), 7.78 (d, J = 4.30 Hz, 2H), 7.69 (t, J = S10

11 7.50 Hz, 2H), 7.52 (d, J = 1.50 Hz, 4H), 7.33 (d, J = 4.15 Hz, 2H), 7.20 (d, J = 8.25 Hz, 8H), 7.14 (d, J = 8.25 Hz, 8H), 2.61 (t, J = 7.70 Hz, 8H), (m, 8H), (m, 24H), (m, 12H). 13 C NMR (125 MHz, CDCl3) δ: , , , , , , , , , , , , , , , , , , , , , , , , , 69.83, 63.19, 35.60, 31.74, 31.36, 29.72, 29.13, MS (MALDI- TOF): m/z (M + ). Synthesis of IDTOT2F Diethyl 2,5-bis(4-(hexyloxy)thiophen-2-yl)terephthalate (5) A mixture of 3 (2.7 g, 7.10 mmol), 4 (9 g, mmol), NaHCO3 (5.96 g, mmol), THF (100 ml) and H2O (12 ml) was carefully degassed before and after Pd(PPh3)4 (95 mg, 0.08 mmol) added. The mixture was refluxed about three days. After being cooled to room temperature, water and ethyl acetate were added, the organic layer was separated. The water phase was washed with ethyl acetate for three times. The combined organic solvent was dried with anhydrous MgSO4 and filtrated, the solvent was moved under reduced atmosphere, and the residue was purified by chromatography on silica gel eluting with petrol ether/dcm (3:1, v/v) to give product 5 (3.02 g) as a light yellow oil in a yield of 73%. 1 H NMR (400 MHz, CDCl3) δ: 7.75 (s, 2H), 7.66 (d, J = 1.68 Hz, 2H), 6.28 (d, J = 1.72 Hz, 2H), (m, 4H), (m, 4H), (m, 4H), (m, 12H), (m, 12H). 13 C NMR (100 MHz, CDCl3) δ: , , , , , , , , , 98.45, 84.14, 70.65, 70.16, 61.71, 31.58, 29.72, 29.23, 29.19, 25.73, 24.74, 22.62, 14.06, S11

12 3,8-bis(hexyloxy)-4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-s-indaceno[1,2- b:5,6-b']dithiophene (6) n-buli (3.9 ml, 2.4mol/L in hexane) was added dropwise to a solution of 1-bromo- 4-hexylbenzene (2.05g, 8.50 mmol) in THF at -78 o C. The mixture was stirred at -78 o C for 1 h and then quenched with a solution of diethyl 2,5-bis(4-(hexyloxy)thiophen- 2-yl)terephthalate (5) (1.0 g, 1.70 mmol) in THF. After kept at -78 o C for 1 h, the reaction was allowed to warm to room temperature and stirred overnight. Water was added to quench the reaction, and the organic layer was separated. The water phase was extracted with ethyl acetate three times. The combined organic layers were dried over MgSO4 and filtrated, the organic solvent was removed by rotary evaporation, and the crude product was directly used without further purification. The crude product was dissolved in anhydrous dichloromethane (50 ml). After carefully degassed, a BF3 Et2O (1 ml) solution was added dropwise. After being stirred for 1 h, methanol was added to quench the reaction. The organic solvent was moved under low pressure, the residue was purified by chromatography on silica gel column eluting with petrol ether to give product 6 (630 mg) as a slight yellow oil in a yield of 34%. 1 H NMR (400 MHz, CDCl3) δ: 7.34 (s, 2H), 7.25 (s, 2H), 7.18 (d, J=5.04 Hz, 8H), 7.00 (d, J=5.28 Hz, 8H), 3.84 (t, J = 4.04 Hz, 4H), 2.53 (t, J = 5.20 Hz, 8H), (m, 16H), (m, 32H), (m, 18H). 13 C NMR (100 MHz, CDCl3) δ: , , , , , , , , , , 98.42, 69.53, 35.60, 31.76, 31.47, 31.32, 29.72, 29.20, 29.04, 25.70, 22.62, 14.12, S12

13 2,7-dibromo-3,8-bis(hexyloxy)-4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-sindaceno[1,2-b:5,6-b']dithiophene (7) NBS (241 mg, 1.35 mmol) was added to a solution of 6 (600 mg, 0.54 mmol) in CHCl3. The reaction was stirred under dark and monitored by TLC. After the reaction was finished, the organic solvent was moved under low pressure. The residue was purified by chromatography on silica gel column eluting with petrol ether to give product 7 (550 mg, 80%) as slight yellow oil. 1 H NMR (400 MHz, CDCl3) δ: 7.23 (s, 2H), 7.17 (d, J = 5.4 Hz, 8H), 7.04 (d, J = 5.4 Hz, 8H), 3.55 (t, J = 4.2 Hz, 4H), 2.55 (t, J = 5.16 Hz, 8H), (m, 16H), (m, 32H), (m, 18H). 13 C NMR (100 MHz, CDCl3) δ: , , , , , , , , , , , , , 98.76, 64.11, 35.57, 32.83, 31.75, 31.56, 31.36, 29.72, 29.13, 25.28, 22.62, 22.60, 22.50, 14.12, ,5'-(3,8-bis(hexyloxy)-4,4,9,9-tetrakis(4-hexylphenyl)-4,9-dihydro-sindaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(thiophene-2-carbaldehyde) (8) A mixture of 7 (500 mg, 0.40 mmol), (5-formylthiophen-2-yl)boronic acid (673 mg, 4.31 mmol), NaHCO3 (336 mg, 4mmol), THF (10 ml) and H2O (2 ml) was carefully degassed before and after Pd(PPh3)4 added. After refluxed under N2 atmosphere overnight, water and ethyl acetate was added, the organic layer was separated. The water phase was washed with ethyl acetate for three times. The combined organic layer was dried with anhydrous MgSO4 and filtrated, the organic solvent was moved under reduced pressure. The residue was purified by chromatography on silica gel column eluting with petrol ether/dcm (2:1) to give product 8 (310 mg, 59%) as an orange oil. S13

14 1 H NMR (400 MHz, CDCl3) δ: 9.83 (s, 2H), 7.62 (d, J = 2.6 Hz, 2H), 7.30 (s, 2H), (m, 10H), 7.07 (d, J = 5.48 Hz, 8H), 3.24 (t, J = 4.76 Hz, 4H), 2.56 (t, J = 5.08 Hz, 8H), (m, 16H), (m, 32H), (m, 18H). 13 C NMR (100 MHz, CDCl3) δ: , , , , , , , , , , , , , , , 77.32, 77.08, 76.82, 75.33, 73.59, 62.06, 35.86, 32.88, 31.56, 31.43, 31.05, 30.27, 29.91, 29.71, 29.22, 25.95, 25.43, 22.65, 22.03, 14.15, ,2'-((2Z,2'Z)-((5,5'-(3,8-bis(hexyloxy)-4,4,9,9-tetrakis(4-hexylphenyl)-4,9- dihydro-s-indaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis(thiophene-5,2 diyl))bis(methanylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1h-indene-2,1 diylidene))dimalononitrile (IDTOT2F) A mixture of 8 (170 mg, 0.13 mmol), 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden- 1-ylidene)malononitrile (150 mg, 0.65 mmol), and CHCl3 (30 ml) was carefully degassed before the addition of 0.5 ml pyridine. After being stirred at room temperature overnight, the solvent was moved under reduced atmosphere. The residue was purified by chromatography on silica gel eluting with petrol ether/dcm (1:1, v/v) to give IDTOT2F (135 mg) as a dark purple solid in a yield of 60%. 1 H NMR (500 MHz, CDCl3) δ: 8.83 (s, 2H), 8.54 (dd, J = 6.55 Hz, J = 9.95 Hz, 2H), 7.81 (d, J = 4.40 Hz, 2H), 7.64 (t, J = 7.40 Hz, 2H), 7.40 (s, 2H), 7.38 (d, J = 4.20 Hz, 2H), 7.29 (d, J = 7.90 Hz, 8H), 7.14 (d, J = 8.40 Hz, 8H), 3.39 (t, J = 7.05 Hz, 4H), 2.62 (t, J = 7.70 Hz, 8H), (m, 4H), (m, 8H), (m, 36 H), (m, 18 H). 13 C NMR (125 MHz, CDCl3) δ: , , , , , , , S14

15 144.19, , , , , , , , , , , , , , 74.26, 68.69, 64.11, 35.55, 31.73, 31.59, 31.37, 29.66, 29.10, 25.16, 22.61, 22.53, 14.11, MS (MALDI-TOF): m/z (M + ). S15