Supplementary Information for: Graphene induced electrical percolation enables more efficient charge transport at a hybrid organic semiconductor/graphene interface Nicolas Boulanger, a Victor Yu, b Michael Hilke, b Michael F. Toney, c and David R. Barbero ∗a Grazing incidence X-ray diffraction (GIXD) data was measured in-situ using an area detector. The samples were placed on a heating stage while the X-ray were incoming at an incident angle φ = 0.13 ◦ (see Fig. S1a). The diffracted beams were collected on an area detector, and formed the diffractograms shown Fig. S1b and c for the films on both graphene and silicon. The polar angle χ is defined as shown on the diffraction patterns at 40 ◦ C, with 0 ◦ being the out-of-plane direction and 90 ◦ the in-plane direction. Heating to 240 ◦ C removed all long-range order formed dur- ing initial spin-coating, and rendered the films disordered. Upon cooling, the film on silicon started to first form edge-on lamellae, visible by a weak 100 z diffraction spot at q≈0.324 Å −1 along the z axis. The first face-on lamellae appeared at ≈160 ◦ C, and their amount remained very low (< 1%) compared to edge-on lamel- lae. On the graphene surface, face-on lamellae first formed at a temperature of ≈205 ◦ C, as shown by the small diffraction peak at approximately the same q in xy. From the grazing incidence data, it was possible to extract po- lar χ plots showing the peaks localization along the χ angle, as defined Fig. S1b,c. An example of such plots for both substrates is shown Fig. S2 for the 100 peak at 180 ◦ C and 40 ◦ C. This allows for visualizing the orientation of the peaks for both the edge-on and face-on orientations. By integrating the polar χ plots for the (100) peak over the a Nano-Engineered Materials & Organic Electronics Laboratory, Umeå University, Umeå, Sweden, E-mail: david.barbero@umu.se b Department of Physics, McGill University, Montréal, Québec, H3A 2T8, Canada c Stanford Synchrotron Radiation Lightsource, Menlo Park, CA, USA whole χ range, it is possible to obtain the total I 1 00 counts and therefore compare the overall amount of crystallites between the film on silicon and the film on graphene, as shown Fig. S3 where it can be seen that the total amount of crystallites is smaller for the film on graphene compared to the film on silicon. Cross-sections along q z have also been extracted to visualize the evolution of the 010 peak in the out-of-plane direction, which is indicative of face-on lamellae formation. Example of such cross- sections are shown Fig. S4a,b during the cooling process at dif- ferent temperatures for both films on silicon and graphene. It is shown that a peak corresponding to face-on lamellae forma- tion appears on graphene as the film is cooled down, whereas no such peak was detected on silicon. Note that due to the graz- ing incidence configuration, the diffraction patterns were taken at an angle of 8 degrees away from the out-of-plane direction in Fig. S4a,b. We moreover also measured the (010) peak on both surfaces using a point detector in the Bragg configuration at room temperature after cooling down on the 2-1 beamline at a 12 keV energy at SSRL. This data provides actual out-of-plane diffraction and is shown Fig. 3b in the article. This confirms that the film on graphene has face-on lamellae, whereas on silicon no diffraction peak could be observed due to the weak amount of face-on. The I-V characteristics of the samples were measured from the bottom to the top of the film, as explained in the article. I-V curves measured at 40 ◦ C are shown in Fig. S5, where the characteristic quadratic evolution of space-charge-limited current (SCLC) cur- rent with applied bias can be observed. 1–3 | 1 Electronic Supplementary Material (ESI) for Physical Chemistry Chemical Physics. This journal is © the Owner Societies 2018