Supplementary Figure 1 In-situ and ex-situ XRD. a) Schematic of the synchrotron based XRD experimental set up for θ-2θ measurements. b) Full in-situ scan of spot deposited film for 800 sec at 325 o C source temperature. Peak intensities are increasing linearly with time; c) Example of integrated peak intensity vs. time at 2θ =19.37 o peak; d) An area detector image of ex-situ full scan for spot-deposited thin film deposited with 1min dwell time. In this case the film obtained shows smooth surface morphology, and some preferential growth is observed (non-uniform intensity distribution along the arc); e) An area detector image for spot-deposited thin film deposited with 10 min dwell time. In this case polycrystalline lobes are formed without preferred orientation (arcs with uniform intensity distribution). 1
Supplementary Figure 2 Thermal expansion coefficient measurement. Thickness variation versus temperature for SubPc film under 1 C/min heating rate. Spectroscopic ellipsometry was used to measure the time dependent thickness changes exhibited by the samples when heating from room temperature to temperature, T, of 250 C, at 1 C/min, using a variable angle spectrometric ellipsometer (M-2000, J.A. Woollam Co.) equipped with an Instec heating stage. The measurements were performed at a fixed angle of 70. The thickness and refractive index, were determined by fitting the acquired ellipsometric angles Δ and Ψ to a Cauchy/SiOx/Si model over the entire measured spectral range (wavelength range 400 1700 nm). During the experiments, the heating stage was purged using purified nitrogen gas to maintain an inert atmosphere and prevent oxidation, and a liquid nitrogen pump was used to maintain the temperature and cooling rates. Extrapolated linear fits were performed to amorphous and crystalline regions of SubPc to calculate the thermal expansion coefficient (see Supplementary Reference 1, eq. 6 for derivation). Amorphous - crystalline transition of SubPc occurs at 150 o C, as seen in the plot. 2
Supplementary Figure 3 Surface element definition. The surface is divided into surface elements, each element is represented by x,y coordinates and angle deviation from flat surface θ. 3
Supplementary Figure 4 Strain energy density W of stressed wavy film. Figure 1a in the main text demonstrates the thermal gradients in a 1 μm thick film deposited at source temperature of 325 o C, with carrier gas jet flow rate of 100 sccm and guard flow rate of 200 sccm. The resulting thermal stresses were then calculated according to the obtained temperature profiles using COMSOL mechanical module and applied to a wavy surface as a tensile stress. The resulting elastic energy density profile in a wavy film is shown here. Maximum energy is obtained at the valleys of the wavy surface and approximated to wave function described in Eq. 5 in the main text. 4
Supplementary Figure 5. PTCDA and Alq 3 morphology a. Morphology of PTCDA deposited at 450 o C source temperature, 5 min dwell time spot deposit. In this case platelet-like growth demonstrated, with deviation angles measured from the surface close to 90 degrees. b. Morphology of Alq 3 deposited at 300 o C source temperature, 1 min dwell time deposit. In this case, lobular features, similar to SubPc, are obtained. Scale bar is 1 μm. 5
Supplementary Figure 6 Contact angle measurement for SubPc films with and without lobes. Here difference in water contact angle is demonstrated for 300 nm thick film (a) and 800 nm film with lobes (b) formed on top. Due to lobes formation, a highly hydrophobic surface is obtained and contact angle is changing from 90±2 o for flat surface to 155±2 o for lobes surface. This demonstrates one of the possible applications of the obtained surfaces. 6
Supplementary Note 1 Ostwald ripening mechanism in OVJP system According to classical Ostwald theory the average particles radius is as follows 2 : Where: <R>- average particle diameter [m] γ- particle surface energy [j m -2 ] R 3 - R 0 3 c - solubility of particle material [mole m -3 ] v- molar volume of particle material [m 3 mole -1 ] D- diffusion coefficient of the particle material [m 2 sec -1 ] Rg- ideal gas constant [J mole -1 K -1 ] T- temperature [K] t- time [sec] = 8gc v2 D 9R g T t (1) Classical Ostwald theory states that diameter cube is proportional to 1/T and t. For the material system and process described in this paper, Ostwald ripening is happening simultaneously with growth due to continuous deposition from the vapor phase. Consequently, the lobe size evolution mechanism is more complex than what is dealt with in the classical Ostwald ripening theory, i.e. particles size changes at constant system volume. We note also that the surface temperature of the deposited film does depend to an extent on a number of process conditions, including gas temperature, gas flow rate, operating 7
pressure, and nozzle proximity. If the vapor temperature (T source ) is varied, the concentration of the molecules in the vapor phase will increase as well. To account for that and keep deposit volume constant, either deposition time should change (Figure 3a), or dilution flow should be introduced. Changing substrate temperature is another approach; in this case, surface molecular diffusivity as well as sticking coefficient will change. 8
Supplementary Note 2 Finite elements modeling for surface evolution. Surface element definition is shown in Supplementary Fig. 3. Basic equation defining the relation between geometry- H matrix, elements points velocities vector [x, y], and elements points forces vector f is given by: H ij éë é ù û ë x 1 y 1 x 2 y 2 ù é = û ë f 1 f 2 f 3 f 4 ù û (2) Supplementary equation 3 describes vector f expressed in terms of material properties: é ë f 1 f 2 f 3 f 4 ù é cosq = g sinq -cosq -sinq û ë ù é + lg 2 û ë -sinq cosq -sinq cosq é ù + l 2 û ë ( 2 3 W 1 + 1 3 W ù 2)sinq -( 2 3 W + 1 1 3 W )cosq 2 ( 1 3 W 1 + 2 3 W 2)sinq -( 1 3 W 1 + 2 3 W 2)cosq û (3) The H matrix is given by: éë H ij ù û = l 6L é 2sin 2 q -2sinq cosq sin 2 q -sinq cosq -2sinq cosq 2cos 2 q -sinq cosq cos 2 q ë sin 2 q -sinq cosq 2sin 2 q -2sinq cosq -sinq cosq cos 2 q -2sinq cosq 2cos 2 q ù û (4) Same approach for surface evolution modeling is used for multiple elements. Each iteration corresponds to single time step. At each iteration the velocity of a surface element is recalculated according to the driving force applied to surface element and 9
migrates according to defined time step and corresponding velocity. Detailed explanation of model can be found in ref. 27 in the main text. The time step used in this study was 0.001 s, and the final surface evolution was calculated for 1000 sec. The surface element size l was 1-10 nm (element size is changing during simulation due to changing surface morphology). 10
Supplementary References 1. Pye, J. E. & Roth, C. B. Physical Aging of Polymer Films Quenched and Measured Free-Standing via Ellipsometry: Controlling Stress Imparted by Thermal Expansion Mismatch between Film and Support. Macromolecules 46, 9455 9463 (2013). 2. Lifshitz, I.M. & Slyozov, V.V. "The Kinetics of Precipitation from Supersaturated Solid Solutions". Journal of Physics and Chemistry of Solids 19, 35 50 (1961). 11