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1 DOI: /NCHEM.1381 The synthesis, crystal structure and charge-transport properties of hexacene Motonori Watanabe, 1 Yuan Jay Chang, 1 Shun-Wei Liu, 2 Ting-Han Chao, 3 Kenta Goto, 4 Md. Minarul Islam, 1 Chih-Hsien Yuan, 1 Yu-Tai Tao, 1 Teruo Shinmyozu, 4 and Tahsin J. Chow 1* 1Institute of Chemistry, Academia Sinica, No.128, Academia Road Sec 2,Nankang, Taipei, 11529, Taiwan. 2Department of Electonic Engineering, Mingchi Chi University of Technology, No. 84, Gongzhuan Rd., Taishan Dist., New Taipei City 24301, Taiwan. 3Department of Chemistry, National Taiwan Normal University, Ting-Chow Rd, Taipei, 11677, Taiwan. 4Institute of Materials Chemistry and Engineering (IMCE), Kyushu University, Hakozaki, Fukuoka, , Japan. tjchow@chem.sinica.edu.tw Table of Contents General procedure and methods Structural data and synthetic procedure 1 H and 13 C NMR spectra UV/Vis spectra MALDI-MS chart Theoretical calculated NMR spectra Stability of hexacene after 30 days Photoemission yield spectroscopy Charge mobility of different acenes according to the function y = ax b Histogram of FET. Single crystal OFET characteristics of pentacene Theoretical calculated atomic coordinates Reference Page number S2~S6 S7~S9 S10 S13 S14 S15 S15 S16 S16 S17 S17 S18 S32 NATURE CHEMISTRY 1

2 General procedure and methods General information Mass spectra were recorded on a VG70-250S mass spectrometer. Elemental analyses were performed on a Perkin-Elmer 2400, CHN analyser. Analytical thin layer chromatography (TLC) was performed on Silica gel 60 F254 Merck. Column chromatography was performed on Merk Kieselgel Si 60 (40-63mm). Absorption spectra were recorded on a Jasco-550 spectrophotometer. Fluorescence spectra were recorded on a HITACHI F-4500 spectrophotometer. TGA were recorded on a Pyris 1 TGA Lab system. IR spectra were measured as KBr pellets and were performed on a Perkin-Elmer spectrum 100. Ionization potential was estimated by photoemission yield spectroscopy in air on an AC-2 Riken. All solvents and reagents were of reagent quality, purchased commercially, and used without further purification. MALDI-TOF/TOF MS were recorded on an Applied Biosystems 4800, Foster City, CA equipped with a 355 nm Nd-YAG laser. The sample was dissolved in dichloromethane first, then an equal amount of this sample solution (1.0 μl) and a 0.5 % dithranol in THF (DIT, 1.0 μl) was mixed together. The resulting mixture (1.0 μl) was spotted onto the stainless steel sample plate for injection. NMR spectroscopy The 1 H and 13 C NMR spectra were recorded on a Bruker AV500 (500 MHz) and AV400 (400 MHz). Chemical shifts are reported as values (ppm) relative to internal Me4Si. The coupling constants (J) are given in hertz. The 13 C CP/MAS NMR spectra were acquired with a Bruker (Spectrospin, Rheinstetten, Germany) Avance 300 MHz NMR spectrometer, equipped with a 4 mm double resonance probe operating at 1 H and 13 C Larmor frequencies of and MHz, respectively. The 1 H to 13 C polarization transfer was optimized to fulfil the Hartman-Hahn matching condition. 1 For the polarization transfer, the contact-time was set to 1 ms, and rf field strengths of 41.0 khz were chosen for both the 1 H and 13 C channels. During data acquisition, 1 H decoupling by TPPM 2 was applied with B1 field strengths of 79.3 khz. Powdered samples were packed in double-bearing 4-mm zirconium oxide MAS rotors. A sample spinning frequency of 9 khz was used and regulated by a spinning controller within 1 Hz. All CP-MAS experiments were carried out at ambient temperature. The 13 C NMR chemical shifts are referenced to the methyl signal ( = ppm) of hexamethylbenzene, which was used as an external standard. All measurements were performed in air, and the sample tube was kept in the dark between measurements. NATURE CHEMISTRY 2

3 FET and Conductivity Characterization The electrical measurements were carried out in air using a semiconductor parameter analyzer (Keithley 2636). The saturation mobility (µsat) was extracted from the slope of the square root of the drain current plot vs VG from equation 1. I D, sat W C V V (1) 2 2L i sat G T where ID,sat is the drain-to-source saturated current; W/L is the channel width to length ratio; Ci is the capacitance of the insulator per unit area, and the VG and VT are gate voltage and threshold voltage, respectively. A heavily doped silicon (si) wafer was used for a back gate electrode, which was covered with a thick layer (~ 300 nm) of thermally grown SiO2 (Ci = 12 nf/cm 2 ) as the gate insulator. Channel length (L) and width (W) were measured using a imaging source color CCD Camera (DBK 41AU02). The conductivity of single crystal hexacene under gate-free condition was extracted from equation 2, dv ds (2) L A di where A is the single crystal cross-sectional area. Field effect transistors were fabricated on a heavily doped Si wafer with a SiO2 layer (300 nm) in a top contact geometry. A SiO2/Si substrate was first cleaned by oxygen plasma, then dipped into a toluene solution of octyltrichlorosilane (OcTS, 0.1 wt%) for 10 min, rinsed with toluene and dried with a nitrogen gun. Crystals of hexacene were grown directly on top of the OcTS/SiO2/Si substrate by inserting it into the glass tube of physical vapor transport (PVT) at the crystal growth region. The glass tube containing hexacene powder was heated in an oven at o C with a flow of argon gas (20-40 ml/min). After then a layer of gold (80 nm) was thermally deposited with a rate of 0.1 nms -1 under a pressure of torr through a shadow mask. For a comparison the device made with pentacene was also made in a similar manner For a comparison the device made with pentacene was also made in a similar manner as that with hexacene. Field effect transistors were fabricated on a heavily doped Si wafer with a SiO2 layer (300 nm) in a top contact geometry. A SiO2/Si substrate was first cleaned by oxygen plasma, then dipped into a toluene solution of octyltrichlorosilane (OcTS, 0.1 wt%) for 10 min, rinsed with toluene and dried with a nitrogen gun. Single crystals of pentacene were deposited onto the OcTS/SiO2/Si substrate by inserting it into the crystal growth area on the glass tube of PVT. The tube containing pentacene powder was heated in an oven at o C with a flow of argon ds NATURE CHEMISTRY 3

4 gas (15-30 ml/min). After then a layer of gold (80 nm) was thermally deposited with a rate of 0.1 nms -1 under a pressure of torr through a shadow mask. X-ray crystallographic study: X-ray crystallographic study was performed using both the graphite-monochromated Mo K radiation and the graphite-monochromated Cu K radiation conditions. Both data gave similar results, i.e. crystal lattice number and space group, etc. The graphite-monochromated Cu K radiation condition data was used for discussion. Graphite-monochromated Mo K radiation Measurements were made using graphite-monochromated Mo K ( = Å) radiation and a rotating anode generator. The crystal structures were solved by direct methods, SIR97, 3 and refined by the full-matrix least-squares methods. The non-hydrogen atoms were refined anisotropically and hydrogen atoms were refined isotropically. The computations were performed using the Crystal Structure 4.0 package. 4 Hexacene-Mo: Crystal color and habit are blue-green and platelet, crystal dimension mm 3, formula C26H16, Mr = , triclinic, space group P-1 (#2), a = 6.306(6), b = 7.697(10), c = 16.48(2) Å, = 98.77(4), = 91.25(3), =95.81(5), V = 786(2) Å 3, Z = 2, Dcalcd = g cm -1, (Mo K ) = cm -1, T = -150 C, F(000) = , Rint = for 3496 observed reflections (I > 2 (I)) and 235 variable parameters, R1 = , GOF = Crystallographic data for the structural analyses of Hexacene-Mo have been deposited with the Cambridge Crystallographic Data Centre (CCDC) as Copies of the data can be obtained free of charge via (or from the Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge, CB2 1EZ, U.K.; Fax: ; deposit@ccdc.cam.ac.uk). Graphite-monochromated Cu K radiation condition Measurements were made using graphite-monochromated Cu K ( = Å) radiation and a rotating anode generator. The crystal structures were solved by direct methods, SIR97, 3 and refined by the full-matrix least-squares methods. The non-hydrogen atoms were refined anisotropically and hydrogen atoms were refined isotropically. The computations were performed using the CrystalStructure 4.0 package. 4 Hexacene-Cu: Crystal color and habit are blue-green and platelet, crystal dimension mm 3, formula C26H16, Mr = , triclinic, space group P-1 (#2), a = 6.292(4), b = 7.673(4), c = (8) Å, =98.66(4), =91.16(4), NATURE CHEMISTRY 4

5 =95.71(4), V = 779.5(7) Å 3, Z = 2, Dcalcd = g cm -1, (Cu K ) = cm -1, T = -150 C, F(000) = , Rint = for 2763 observed reflections (I > 2 (I)) and 235 variable parameters, R1 = , GOF = Crystallographic data for the structural analyses of Hexacene-Cu have been deposited with the Cambridge Crystallographic Data Centre (CCDC) as Copies of the data can be obtained free of charge via (or from the Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge, CB2 1EZ, U.K.; Fax: ; deposit@ccdc.cam.ac.uk). Theoretical calculation Calculating NMR Geometry optimization of hexacene and its precursor 1 were carried out by the DFT method at the M06 5 /6-31G(d) level using Gaussian09 6 suite of programs. The frequency analysis was carried out for the optimized structures to give no imaginary frequency. Calculating NMR by GIAO method 7-11 for precursor 1 and hexacene were carried out by B3LYP /6-311+G(2d,p) level. The structure of Me4Si was used as a reference at B3LYP/6-311+G(2d,p) level in the GaussView 5 software. 15 Calculating reorganization energy Intramolecular reorganization energy + can be estimated from equation N C (3) N EN rel E (4) N C EC rel E (5) C Here, EN(rel) and EN are the energies of the neutral state at the cation geometry and optimized ground state geometry, and EC(rel) and Ec are the energies of the radical cation at the neutral geometry and optimized radical cation geometry, respectively. Geometry optimization of tetracene, pentacene, and hexacene were carried out by the DFT method for neutral ground state and radical cation state at the B3LYP/6-31G(d,p) level using Gaussian09 6 suite of programs, followed by neutral state of cation geometry and radical cation of the neutral geometry single-point energy were estimated by the B3LYP/6-31G(d,p) level. The frequency analysis was carried out for the optimized structures to give no imaginary frequency. Calculating hole transporting properties The rate of electronic transfer (ket) can be explained by Marcus theory 17, NATURE CHEMISTRY 5

6 K ET t exp kbt 4kBT here, ћ is a plank constant, + is reorganization energy, t + is the electronic coupling between two molecules. The electronic coupling (t) is calculated directly from the spatial overlap (SSP), charge transfer integrals (HRP) and site energies (HRR, HPP). The electronic coupling is given by t (6) H S H H / 2 (7) SP RP 1 S RR 2 RP All electronic couplings were performed using the Amsterdam density functional (ADF) theory program 18 which has been employed for calculating the electronic coupling at PW91 19 /DZ2P level. After calculations of electronic transfer (ket), the diffusion coefficient D was calculated by equation 8, D 2n PP 1 2 i ri keti P (8) i where n = 3 is dimensionally, and keti, is the hopping rate due to charge transfer to the i-th neighbor molecules at a centroid distance of ri. P is the relative probability that hopping will happen between the i-th neighbor molecules as follows, P Hole transporting property of + can be calculated by Einstein equation 20, i keti k i ETi (9) e D k T B (10) where e is the electron charge. T was used as 300 K. Only nearest neighbor hopping terms are estimated. The calculated mobility ( + ) in Table 1 in the main text was displayed as an average value of the four directions (T1, T2, P, and L) under consideration. NATURE CHEMISTRY 6

7 Structural data and synthetic procedure Scheme S1 Synthetic scheme of hexacene precursor 1. a; 3,6-bis(2-pyridyl)-tetrazine, toluene, 59%. b; NaBH4, THF, MeOH. c; POCl3, NaI, pyridine, 54% (2 steps from 4). d; OsO4, N-methylmorpholine N-oxide (NMO), acetone, H2O. e; PdI(OAc)2, benzene, 74% (2 steps from 6) (1R,4S)-11-(propan-2-ylidene)-1,4-dihydro-1,4-methanoanthracene 2: To a solution of 1,2-dichloroethane (80 ml) containing isopentyl nitrate (1.39 ml) and 6,6-dimethylfulvene (0.93 ml) under reflux was added dropwise a solution of 3-amino-2-naphthoic acid (1.32 g, 7.05 mmol) in THF (90 ml) over 1 h in a nitrogen atmosphere. After cooling, the reaction mixture was concentrated and the crude product was purified by a silica gel column chromatograph eluted with hexane to afford the adduct 2 (874 mg, 53%) as white solids. Physical data of 2: colorless crystals (EtOH). Mp ºC (sealed); 1 H NMR (CDCl3, 500MHz) 1.58 (s, 6H), 4.45 (t, J=2.0 Hz, 2H), 6.87 (dd, J = 2.0 Hz, 2H), 7.36 (dd, J = 6.0, 3.5 Hz, 2H), 7.57 (s, 2H), 7.69 (dd, J = 6.0, 3.5 Hz, 2H), 8.36 (s, 1H), 8.44 (s, 1H); 13 CNMR (CDCl3, 125 MHz) 19.1, 50.0, 105.6, 118.4, 125.2, 127.6, 132.0, 142.0, 147.1, 158.8; IR (KBr) 3007 (m, C=C) cm -1 ; HR-EIMS m/z (M + ) calcd , obsed ; Anal. Calcd. for C18H16: C, 93.06; H, Found: C, 92.96; H, NATURE CHEMISTRY 7

8 (6R,6aR,14aS,15S)-17-(propan-2-ylidene)-6,6a,14a,15-tetrahydro-6,15-methanohexacen e-7,14-dione 4: To a mixture of 2 (232 mg, 1.0 mmol), anthracene-1,4-dione 3 (208 mg, 1.0 mmol), and 3,6-bis(2-pyridyl)tetrazine (248 mg, 1.05 mmol) in toluene (50 ml) was refluxed for 23 h under a nitrogen atmosphere. After the reaction, the mixture was quenched with 30% H2SO4, washed with brine, extracted with CH2Cl2, and the organic solution was dried over MgSO4 and concentrated in vacuo. The crude product was purified by a silica gel chromatograph eluted with CH2Cl2 to afford a mixture of endo and exo geometrical isomers of 4 (243 mg, 59%) as yellow solids. Physical data of 4: 1 H NMR (CDCl3, 500 MHz) 1.24 (s, 6H), 1.77 (s, 6H), 3.17 (s, 2H), 3.78 (dd, J=2.75, 1.75 Hz, 2H), 4.49 (s, 2H), 4.66 (dd, J =2.75, 1.75 Hz, 2H), 7.14 (dd, J =6.25, 3.25 Hz, 2H), (m, 8H), 7.71 (dd, J =6.25, 3.25 Hz, 2H), (m, 6H), 8.09 (dd, J =6.25, 3.25 Hz, 2H), 8.29 (s, 2H), 8.65 (s, 2H); IR (mixture) (KBr) 1677, 1621 (s, C=O) cm -1 ; HR-EIMS m/z (mixture) (M + ); calcd; , obsd; ; Anal. calcd. (mixture) for C18H16: C, 86.93; H, Found: C, 86.67; H, (6R,15S)-17-(propan-2-ylidene)-6,15-dihydro-6,15-methanohexacene 6: To a solution of dione 4 (243 mg, mmol) in MeOH (25 ml) and THF (25 ml) was added NaBH4 (45 mg, 1.19 mmol) in an ice bath. After 2 h, the reaction mixture was quenched with 3N HCl, then poured into water. The aqueous solution containing precipitates was neutralized with saturated NaHCO3, then extracted with CH2Cl2. The organic layer was washed with water, and dried over anhydrous MgSO4. Removal the solvent gave the diol 5 as yellow solids. This crude compound was subjected to the next step without further purification. To a mixture of diol 5 and dried pyridine (10 ml) was added dropwise POCl3 (0.3 ml) at 0 0 C. The resulting mixture was stirred at room NATURE CHEMISTRY 8

9 temperature for 16 h, then at 80 0 C for another 30 min. The mixture was poured into ice water and was extracted with CH2Cl2. The organic layer was washed successfully with 3N HCl and brine, then was dried over MgSO4. The crude product was purified by a silica gel chromatograph eluted with hexane/ch2cl2 (4:1) to give the aromatized compound 6 (120 mg 54 %) as pale yellow powder. Physical data of 6: pale yellow needls (EtOH). Mp ºC (sealed); 1 H NMR (CDCl3, 500 MHz) 1.73 (s, 6H), 5.06 (s, 2H), 7.35 (dd,, J = 6.3, 3.3 Hz, 2H), 7.39 (dd, J = 6.5, 3.0 Hz, 2H), 7.70 (dd, J = 6.3, 3.3 Hz, 2H), 7.73 (s, 2H),7.80 (s, 2H), 7.92 (dd, J = 6.3, 3.3 Hz, 2H),8.23 (s, 2H); 13 CNMR (CDCl3, 125 MHz) 19.8, 51.4, 112.9, 118.3, 118.9, 124.9, 125.4, 125.8, 127.7, 127.9, 131.1, 131.6, 132.4, 144.8, 145.4, 154.0; IR (KBr): 2991 (m, C=C) cm -1 ; HR-EIMS m/z (M + ); calcd; , obsd; ; Anal. calcd. for C18H16: C, 94.20; H, Found: C, 93.95; H, (6R,15S)-6,15-dihydro-6,15-methanohexacen-17-one 1: A mixture of olefin 6 (535 mg, 1.40 mmol) and N-methylmorpholine N-oxide (NMO) (50% in H2O, 4.3 ml) in a mixed solvent of acetone (80 ml) and H2O (4.3 ml) was stirred at room temperature until 6 was dissolved completely. To the solution was added a few drops of OsO4 (4% H2O soln.). The reaction was monitored by TLC until completion, then the mixture was quenched with 15% Na2S2O4. The aqueous solution was extracted with EtOAc, dried over Na2SO4, and evaporated in vacuo. The crude product was purified by a silica gel chromatograph eluted with CH2Cl2 to give diol 7 (484 mg), which was directly used in the next step. HR-EIMS (EI) m/z (M+) calcd; , obsd; The diol 7 (484 mg) and PhI(OAc)2 (736 mg) in benzene (130 ml) was stirred at 60 ºC for 12 h. After reaction, the mixture was cooled in an ice bath, while white precipitates formed. The solids were collected by suction filtration to give compound 1 (371 mg, 74 % in two steps) as a white powder. Physical data of 1: mp 171 ºC (sealed, decomp); 1 H NMR (THF-d8, 400 MHz) 5.03 (s, 2H), (m, 4H), 7.81 (dd, J = 6.2, 3.4 Hz, 2H), 7.97 (dd, J = 6.2, 3.4 Hz, 2H), 7.94 (s, 2H), 8.10 (s, 2H), 8.42 (s, 2H); IR (KBr): 1784 (s, C=O) cm -1 ;HR-EIMS m/z ([M-CO] + ); calcd; , obsd; ; HR-FABMS m/z ([M+H] + ); calcd; , obsd; NATURE CHEMISTRY 9

10 1HNMR and 13 CNMR spectra ppm Figure S1 1 H NMR (500 MHz) spectrum of 2 in CDCl ppm Figure S2 13 C NMR (125 MHz) spectrum of 2 in CDCl3. NATURE CHEMISTRY 10

11 ppm Figure S3 1 H NMR (500 MHz) spectrum of endo-/exo-4 in CDCl ppm Figure S4 1 H NMR (500 MHz) spectrum of 6 in CDCl3. NATURE CHEMISTRY 11

12 ppm Figure S5 13 C NMR (125 MHz) spectrum of 6 in CDCl ppm Figure S6 1 H NMR (400 MHz) spectrum of 1 in THF-d8. The peaks at δ 1.75 and 3.55 are derived from THF, and the one at δ 2.45 from water. NATURE CHEMISTRY 12

13 UV/Vis spectra a Absorbance Wavelength (nm) Fluorescence (a. u.) b Absorbance s 15 s s 60 s Wavelength (nm) Wavelength (nm) Figure S7 a, UV/Vis and fluorescence spectra of precursor 1 in a M THF solution at 298 K. b, UV/Vis spectra of 1 in a 2.0 x10-4 M THF solution at 298 K with photogeneration of hexacene at 385 nm exposure under an O2 free environment. Inset: enlarged in the range of nm. Abs precursor 1 Absorbance Wavelength (nm) Figure S8 UV/Vis spectra of thin-film state of precursor 1. NATURE CHEMISTRY 13

14 MALDI-MS chart Mass (m/z) Figure S9 MALDI-MS chart of hexacene. Figure S10 MALDI-MS chart of hexacene thin-film after irradiation for 300 min. a, detected species of hexacene, and b, detected species of endoperoxide. NATURE CHEMISTRY 14

15 Theoretical calculated NMR spectra a b * * * * ppm ppm Figure S11 Theoretical Calculated NMR spectra of a, precursor 1, and b, hexacene at B3LYP/6-311+G(2d,p)//M06/6-31G(d) level. Red line: fitted theoretical calculation results. Black line: experimental results. Asterisks denote spinning sidebands. Stability of hexacene after 30 days a 0 day b * * 1 day * * 10 day * * 30 day * * ppm Figure S12 A sample of hexacene was kept in air at room temperature in the dark for 30 days. a, CP-MAS NMR spectra, where asterisks denote spinning sidebands. b, Absorption spectra. Inset is time-dependant relative absorption intensity at 840 nm. NATURE CHEMISTRY 15

16 Photoemission yield spectroscopy: Figure S13 Photoemission yield spectra of hexacene (red circle) and pentacene (blue circle) in air. Charge mobility of different acenes according to the function y = ax b 2.5 Mobility (cm 2 s -1 V -1 ) x Figure S14 Calculated charge mobility of different acenes according to the function y = ax b, where the dots (x =2-6) denote the number of aromatic rings. a = , b = R 2 = NATURE CHEMISTRY 16

17 Histogram of FET Figure S15 Histogram of FET charge mobility, measured from the devices made with the single crystals of hexacene. Single crystal OFET characteristics of pentacene I DS ( A) V -60 V -I DS 1/2 (10-2 A) V , -20 V V DS (V) V G (V) Log(-I DS ) (A) Figure S16 a, Output characteristics. Inset shows a crystal across the electrodes, scale bar is 100 m. W/L = b, Transfer characteristics recorded at VDS = -80V. NATURE CHEMISTRY 17

18 Theoretical calculated atomic coordinates Table S1. Coordination of the precursor 1 at MP2/6-31G(d) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 18

19 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S2. Atomic coordinates of hexacene at MP2/6-31G(d) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 19

20 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S3. Atomic coordinates of naphthalene at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 20

21 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S4. Atomic coordination of naphthalene radical cation state at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 21

22 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S5. Atomic coordinates of anthracene at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 22

23 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S6. Atomic coordinates of anthracene radical cation at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 23

24 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S7. Atomic coordinates of tetracene at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 24

25 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S8. Atomic coordinates of tetracene radical cation at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 25

26 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S9. Atomic coordinates of pentacene at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 26

27 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S10. Atomic coordinates of pentacene radical cation at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 27

28 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S11. Atomic coordination of hexacene at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 28

29 NATURE CHEMISTRY 29

30 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= Table S12. Atomic coordinates of hexacene radical cation at B3LYP/6-31G(d,p) level Center Atomic Atomic Coordinates (Angstroms) Number Number Type X Y Z NATURE CHEMISTRY 30

31 Zero-point correction= (Hartree/Particle) Sum of electronic and zero-point Energies= NATURE CHEMISTRY 31

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33 transfer process in -conjugated oligomers and polymers: A molecular picture. Chem. Rev. 104, (2004). 17. Marcus, R. A. Electron transfer reactions in chemistry. Theory and experiment. Rev. Mod. Phys. 65, (1993). 18. te Velde, G. et al. Chemitry with ADF. J. Comput. Chem. 22, (2001). 19. Perdew, J. P. & Wang, Y. Accurate and simple analytic representation of the electron-gas correlation energy. Phys. Rev. B. 45, (1992). 20. Bisquert, J. Interpretation of electron diffusion coefficient in organic and inorganic semiconductors with broad distributions of states. Phys. Chem. Chem. Phys. 10, (2008). NATURE CHEMISTRY 33