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1 SUPPLEMENTARY INFORMATION doi: /nature10683 Supplementary Methods and Discussion: Possibility of Toluene Inclusion in Unit Cell: The unit cell calculations show modest, non-systematic cell volume expansion (< 2%), which is consistent with lack of solvent inclusion. The calculations also showed an excellent fit without the inclusion of solvent molecules (Supplementary Table 1). The strained GIXD pattern was not affected by heating the thin films up to a temperature of 160 o C, well beyond the boiling point of toluene, although the GIXD pattern showed reduction in the intensity of the Bragg peaks. Additionally, the presence of toluene molecules in the unit cell would likely degrade the charge carrier mobility of the thin film transistor (TFT) devices, rather than improve electronic performance. Moreover, the film sheared at a low speed (0.4 mm/s) showed the same GIXD pattern as that of evaporated thin film, which had no solvent inclusion. GIXD Fitting Method: In the GIXD image of the sample prepared at 8mm/s, multiple phases of TIPS-pentacene can be identified. However, one of these phases produces a significantly stronger scattering signal than the other phases and is thus likely to be dominantly present in the 8mm/s samples. Only the sample sheared at 8 mm/s was modeled, as all other speeds resulted in anisotropic crystallite texture, such that molecular packing could not be determined easily. For the strained sample sheared at 8 mm/s, a self-consistent set of 20 peaks (12 non-degenerate positions) was identified. The GIXD image after solvent-annealing with toluene for 60 min show a single phase, for which a self-consistent set of 30 peaks (15 non-degenerate positions) could be devised. The corresponding unit cell geometries were determined by least-square-error optimization fitting of the peak positions. Integrated intensities of these peaks were measured after background 1

2 RESEARCH SUPPLEMENTARY INFORMATION subtraction (using WxDiff, 3 rd order-polynomial background fit). Here, special care was taken to include only those peaks that do not significantly overlap with neighboring peaks so as to allow effective background removal and obtain the best possible integral values. The molecular arrangements of TIPS-pentacene in the unit cells were obtained from a crystallographic refinement procedure. 31 The unit cell volumes of both measured phases (before and after toluene vapor annealing) are compatible with the assumption of a single TIPSpentacene molecule per unit cell. During the refinement procedure the 3 Euler angles of the TIPS-pentacene molecule are varied in such a fashion that the difference between theoretical and experimental integrated peak intensities is minimized (Supplementary Fig. 7). Transfer Integral Calculations: To computationally explore the marked increase in the measured mobilities in the strained film, we have focused calculation on the evaporated and the sheared film at 8mm/s of TIPS-pentacene. Within the single-electron picture 32, the transfer integrals for the nearest-neighbor pairs of molecules (Supplementary Fig. 8) are calculated using Density functional theory employing the B3LYP functional 33 and the 6-31G(d,p) 34 basis set, as implemented in the Q-Chem software package. 35 To take into account the site energy differences of the monomers, we employed a method for calculation of effective transfer integral values where the different electronic environments of the monomers are considered Supplementary Table 2 summarizes the effective transfer integrals for the unique molecular pairs in the evaporated and sheared films. The corresponding pairs T1 and T2 are shown in Supplementary Fig. 8. The transfer integrals indicate a 3-fold increase in the HOMO couplings for T1 pair from 11.7 mev for evaporated film 2

3 SUPPLEMENTARY INFORMATION RESEARCH to 36.9 mev for sheared films at 8 mm/s. The weak coupling in the T2 pair of the sheared film suggests one-dimensional transport along the closely-packed T1 pairs. 3

4 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Figures and Legends: Supplementary Fig. 1: Schematic of the solution shearing device (not drawn to scale). ν, θ and d are the solution shearing speed, angle of the blade with respect to the substrate, and the gap between the edge of the shearing blade and the substrate, respectively. As the blade is withdrawn by the linear translation stage, the TIPS-pentacene solution evaporates and a thin film is cast on the substrate. Vacuum holds the blade in place. The zoomed-in region shows the schematic of OSC and solution flow towards the growing crystal. 4

5 SUPPLEMENTARY INFORMATION RESEARCH Supplementary Fig. 2: Optical characterization of the solution sheared TIPS-pentacene thin films. a, d, g, j, m. Optical micrographs of solution sheared TIPS-pentacene thin films, formed with shearing speed 0.4 mm/s, 1.6 mm/s, 2.8 mm/s, 4 mm/s and 8 mm/s, respectively. b, e, h, k, n. Cross polarized optical microscope (CPOM) images of the same regions as in a, d, g, j, m, respectively. c, f, i, l, o. CPOM images of the same regions as in a, d, g, j, m, with the samples rotated at an angle. Dark regions of the images are due to domains oriented along the polarization direction of the light. In all cases the white arrow represents the shearing direction. The scale bar is 1mm. 5

6 RESEARCH SUPPLEMENTARY INFORMATION 16.9 (001) d-spacing (Å) Speed (mm/s) Supplementary Fig. 3: The (001) d-spacing as a function of shearing speed. The (001) d- spacing varies by < 2% between all shearing speeds, and is not systematic. This indicates that the major distortion is in the plane of the substrate for the TIPS-pentacene unit cell. The dashed lines show 95% confidence interval for the average (001) d-spacing. 6

7 SUPPLEMENTARY INFORMATION RESEARCH Supplementary Fig. 4: Incremental GIXD signal change as a function of shearing speed. Incremental change in the GIXD signal used to calculate the (010) d-spacing change in solution sheared TIPS-pentacene thin films as a function of shearing speed. The intensity of each scan is normalized, and the scans are manually vertically offset for clarity. A gradual shift in the peak position can be seen with increasing shearing speed. The peak broadening seen at higher shearing speeds is caused by various reasons, including an increased density of defects in the thin film, smaller crystallites formed at higher shearing speeds and the presence of crystals with different degrees of lattice strain (strain polymorphs) within the sample volume probed by the GIXD beam.. The low signal-to-noise ratio at higher shearing speeds is caused by the loss of anisotropy of the crystallite texture (Fig. 1e,f). 7

8 RESEARCH SUPPLEMENTARY INFORMATION d-spacing (Å) mm/s (010) d-spacing mm/s (010) d-spacing mm/s (101) d-spacing mm/s (101) d-spacing Thickness (nm) Supplementary Fig. 5: Thickness dependence of lattice parameter shift. This graph shows the relationship between thin film thickness and the (010) (2.8 mm/s, 8 mm/s ) and (101) d- spacing (2.8mm/s, 8 mm/s ) of thin films sheared at a speed of 2.8 mm/s and 8 mm/s. The d-spacing shift for each shearing speed is preserved for a wide range of thin film thickness. In addition, different (101) and (010) d-spacing, caused by different shearing speed, occur at the same film thickness. Thus, the in-plane lattice parameter shift of the TIPS-pentacene unit cell is not due to the formation of strained phases in thinner films, i.e. in film regions at a smaller distance from the substrate surface, below unstrained film portions. 8

9 SUPPLEMENTARY INFORMATION RESEARCH Supplementary Fig. 6: Effect of toluene vapor annealing on d-spacing. Effect of toluene vapor annealing on a. (101) (Before, After ) and b. (010) (Before, After ) d-spacing of solution sheared TIPS-pentacene thin films. The samples were exposed to toluene for an hour and were stored under vacuum overnight to remove residual solvent molecules. The d-spacing in the plane of the substrate surface becomes similar to the unstrained values after exposure to toluene. * The GIXD pattern of the sample sheared at 0.4mm/s did not show the (101) Bragg peak, the (103) Bragg peak was used for this data point. 9

10 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Fig. 7: The measured and calculated diffraction intensities (best-fit) for TIPS-pentacene films. TIPS-pentacene films prepared at 8mm/s shearing speed a. before solvent annealing and b. after solvent annealing with toluene vapor. The diffraction intensity is indicated by the area of half-circles. The gray half of each circle is the observed (measured) diffraction intensity, and the black half is the calculated diffraction intensity. The size comparison of the two half-circles indicates a strong fit. In order to provide the crystallographic information of the thin film structure in the widely used.cif format we have compiled two cif files, one for the strained TIPS-pentacene structure (solution sheared at 8 mm/s), and one for the relaxed bulk-like TIPS-pentacene structure obtained after solvent-annealing the former strained phase. Please note that there are substantial differences between our refinement procedure and refinement that is performed on data sets from bulk single crystals with thousands of hkl reflections. Specifically, these models represent the respective best fit structures that one can obtain from fitting the calculated diffraction intensities to the measured ones under variation of the Euler angles of the rigid, bulk-like TIPS-pentacene molecules in the respective thin film unit cells. The limited number of available reflections makes these assumptions necessary; and the 10

11 SUPPLEMENTARY INFORMATION RESEARCH resulting models are therefore not of the quality of refined bulk crystal data in which the atom positions are fitted individually and are primarily intended to visualize the differences between the strained and un-strained polymorphs. Additional information is provided in the supplementary text. 11

12 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Fig. 8: Crystal structure of TIPS-pentacene thin films sheared at 8 mm/s. Labels correspond to the molecular pairs used in the transfer integral calculations. 12

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14 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Fig. 9: Impact of molecular long and short axis displacements for the strained TIPS-pentacene thin films sheared at 8 mm/s. In all calculations, the π-π stacking distance is fixed at 3.08 Å. a. T1 pair transfer integral as a function of TIPS-pentacene dimer displacement along the long molecular axis. The green point indicates position of strained TIPSpentacene T1 pair observed from solution shearing at 8 mm/s. The transfer integral of the strained TIPS-pentacene is close to the optimized displacement. b. T1 pair transfer integral as a function of TIPS-pentacene dimer displacement along the short molecular axis. The green point indicates position of strained TIPS-pentacene T1 pair we observed from solution shearing at 8 mm/s. The transfer integral of the TIPS-pentacene is not optimized compared to a cofacial dimer packing, where the transfer integral would be mev. c. T1 pair transfer integral as a function of long axis displacement for a hypothetical case of perfect cofacial packing. The dimer displaced by 1.5 Å (3rd picture) shows T1 transfer integral if the strained TIPS-pentacene had perfect cofacial packing. The transfer integral is mev compared to mev for the T1 transfer integral of the TIPS-pentacene thin film solution sheared at 8 mm/s. 14

15 SUPPLEMENTARY INFORMATION RESEARCH Supplementary Fig. 10: Histograms of high performance devices. a. Histogram of TFT mobility of TIPS-pentacene thin films cast at a shearing speed of 2.6 mm/s. b. Histogram of TFT mobility of TIPS-pentacene thin films cast at a shearing speed of 2.8 mm/s. 15

16 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Fig. 11: Effect of toluene vapor exposure on crystallite texture. a, d and g. show CPOM images of a TIPS-pentacene thin film solution sheared at 2.4 mm/s before exposure to toluene vapor, after exposure to toluene vapor for 5 min, and after exposure for 60 min, respectively. The scale bar is 50 microns. b, e and h. Representative AFM image of a TIPSpentacene thin film solution sheared at 2.4 mm/s before exposure to toluene vapor, after exposure to toluene vapor for 5 min, and after exposure for 60 min, respectively. The AFM height scale is 30 nm. The size of the AFM image is 5x5 microns. c, f and i. Closed traces show representative GIXD scans of the Bragg peak used to calculate (101) d-spacing in TIPSpentacene thin film solution sheared at 2.4 mm/s before exposure to toluene vapor, after exposure to toluene vapor for 5 min, and after exposure for 60 min, respectively. Open trace shows GIXD scan of sample sheared at 0.4 mm/s. A line is placed at the peak position of the strained sample sheared at 2.4 mm/s to guide the eye. No surface morphology change can be seen on the TIPS-pentacene thin film with AFM after 5 min exposure to toluene vapor, but 16

17 SUPPLEMENTARY INFORMATION RESEARCH change in the GIXD pattern (a growth of a shoulder peak at q xy = 0.83) can be seen which points towards a less strained molecular packing. At longer exposure times, cracks begin to appear in the thin film, and the GIXD image shows that the film becomes further relaxed. 17

18 RESEARCH SUPPLEMENTARY INFORMATION Normalized Mobility Speed (mm/s) Supplementary Fig. 12: Effect of toluene vapor on mobility of TIPS-pentacene TFTs fabricated with different shearing speeds. The average mobility before toluene vapor exposure is normalized at 100% for each device, shown by the dashed line. The error bars show the standard deviation, where at least 5 samples were tested. The samples were exposed to toluene for 5 min. For all strained thin films, toluene vapor exposure lowers the mobility. The thin films prepared at a shearing speed of 0.4 mm/s show a slight increase in mobility after toluene vapor exposure, which is similar to observations in previous reports, due to improvement of grain connectivity. 38 This result indicates that the alteration of molecular packing induced by solution shearing at speeds above 0.4 mm/s is the key factor leading to increased charge carrier mobility, until the mobility subsequently decreases due to grain boundaries and the formation of isotropic crystallites. 18

19 SUPPLEMENTARY INFORMATION RESEARCH Supplementary Fig. 13: Incremental peak position change and charge transport enhancement in different OSCs. a. Incremental change in the peak position for solution sheared F-TES-ADT thin films as a function of shearing speed. The intensity of each scan is normalized such that the maximum intensities are equal. The inset shows the chemical structure of F-TES-ADT. b. Mobility of TFTs made from F-TES-ADT thin films solution sheared at different shearing speeds. The error bars show the standard deviation of the mobility. c. Incremental change in the XRD signal of the (002) peak for solution sheared 4T-TMS thin films as a function of shearing speed. The intensity of each scan is normalized such that the maximum intensities are equal. The inset shows the chemical structure of 4T-TMS. 19

20 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Tables: Speed a b c α β γ Cell d-spacing Mobility On/Off Vt Volume (100) (010) (mm/s) (Å) (Å) (Å) (deg) (deg) (deg) (ų) (Å) (Å) (cm²/vs) (V) Evaporated (14.3) 7.70 (0.07) 7.80 (0.11) E (7.5) 7.65 (0.05) 7.86 (0.07) E (8.2) 7.60 (0.03) 7.89 (0.03) E (19.5) 7.45 (0.07) 8.05 (0.06) E (6.7) 7.26 (0.08) 8.13 (0.06) E * (3.6) Supplementary Table 1: d-spacing parameters and unit cell parameters of sheared TIPSpentacene thin films. Average values of (101) d-spacing and (010) d-spacing of solution sheared TIPS-pentacene thin films, and the TIPS-pentacene unit cell parameters as a function of shearing speeds. Standard deviation is shown in parentheses. * Sample was annealed in toluene vapor for 1hr. Molecular Pair Evaporated thin film (T1) Evaporated thin film (T2) Thin film sheared at 8 mm/s (T1) Thin film sheared at 8 mm/s (T2) Transfer Integral (mev) Center-of-mass Distance (Å) Supplementary Table 2: Effective transfer integrals for unique molecular pairs in the crystal structures. T1 and T2 are unique molecular pairs identified in Fig. 3a,b. 20

21 SUPPLEMENTARY INFORMATION RESEARCH Speed Devices Mobility On/Off Ratio Threshold Voltage Max. Current Maximum Average St. Dev. SEM Average St. Dev. Average St. Dev. Average St. Dev. (mm/s) (#) (cm^2/vs) (cm^2/vs) (cm^2/vs) (cm^2/vs) (V) (V) (A) (A) E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E-05 Supplementary Table 3: Thin film transistor (TFT) electrical characteristics of solution sheared TIPS-pentacene thin films, measured along the direction of shearing. The standard error of the mean (SEM) is calculated by dividing the standard deviation by the square root of the number of samples. Speed Devices Mobility On/Off Ratio Threshold Voltage Max. Current Maximum Average St. Dev. SEM Average St. Dev. Average St. Dev. Average St. Dev. (mm/s) (#) (cm^2/vs) (cm^2/vs) (cm^2/vs) (cm^2/vs) (V) (V) (A) (A) E+07 5E yr E+07 1E Supplementary Table 4: Long-term stability of high mobility TFTs fabricated from lattice strained TIPS-pentacene thin films. The standard error of the mean (SEM) is calculated by dividing the standard deviation by the square root of the number of samples. 21

22 RESEARCH SUPPLEMENTARY INFORMATION Supplementary Video 1: Toluene solvent annealing video. GIXD performed on TIPSpentacene thin film which was cast with a shearing speed of 2.8 mm/s. The sample was exposed to toluene vapor in-situ, so the relaxation of the Bragg peaks that represent the (101) d-spacing (top) and (010) d-spacing (bottom) lattice parameters is evident with increased toluene vapor exposure. Supplementary Video 2: In situ thermal annealing video. GIXD performed on lattice strained TIPS-pentacene thin film, cast with a shearing speed of 8 mm/s. The sample was heated from room temperature to 160 C. The video of the Bragg peak that represents the (010) d-spacing is shown. Thermal lattice expansion is present out of the plane of the substrate, shown by the decreasing Q z values at higher temperatures. The Q xy values do not change, indicating that the inplane lattice strain caused by solution shearing does not change. The film does not return to the equilibrium packing state upon heating, indicating the thermal stability of the lattice strain. 22

23 SUPPLEMENTARY INFORMATION RESEARCH References: 31 Mannsfeld, S. C. B., Tang, M. L. & Bao, Z. Thin Film Structure of Triisopropylsilylethynyl-Functionalized Pentacene and Tetraceno[2,3-b]thiophene from Grazing Incidence X-Ray Diffraction. Advanced Materials 23, , doi: /adma (2011). 32 Valeev, E. F., Coropceanu, V., da Silva Filho, D. A., Salman, S. & Brédas, J.-L. Effect of Electronic Polarization on Charge-Transport Parameters in Molecular Organic Semiconductors. Journal of the American Chemical Society 128, , doi: /ja061827h (2006). 33 Lee, C., Yang, W. & Parr, R. G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Physical Review B 37, 785 (1988). 34 Francl, M. M. et al. Self-consistent molecular orbital methods. XXIII. A polarizationtype basis set for second-row elements. Journal Name: J. Chem. Phys.; (United States); Journal Volume: 77:7, Medium: X; Size: Pages: (1982). 35 Shao, Y. et al. Advances in methods and algorithms in a modern quantum chemistry program package. Physical Chemistry Chemical Physics 8, (2006). 36 Norton, J. E. & Bredas, J.-L. Theoretical characterization of titanyl phthalocyanine as a p-type organic semiconductor: Short intermolecular pi-pi interactions yield large electronic couplings and hole transport bandwidths. The Journal of Chemical Physics 128, (2008). 37 Senthilkumar, K., Grozema, F. C., Bickelhaupt, F. M. & Siebbeles, L. D. A. Charge transport in columnar stacked triphenylenes: Effects of conformational fluctuations on 23

24 RESEARCH SUPPLEMENTARY INFORMATION charge transfer integrals and site energies. The Journal of Chemical Physics 119, (2003). 38 Kim, K. H., Chung, D. S., Park, C. E. & Choi, D. H. High performance semiconducting polymers containing bis(bithiophenyl dithienothiophene)-based repeating groups for organic thin film transistors. Journal of Polymer Science Part A: Polymer Chemistry 49, 55-64, doi: /pola (2011). 24