Supporting Information

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1 Copyright WILEY VCH Verlag GmbH & Co. KGaA, Weinheim, Germany, Supporting Information for Adv. Mater., DOI: /adma High Charge-Carrier Mobility of 2.5 cm 2 V 1 s 1 from a Water-Borne Colloid of a Polymeric Semiconductor via Smart Surfactant Engineering Jangwhan Cho, Kwang Hee Cheon, Hyungju Ahn, Kwang Hun Park, Soon-Ki Kwon, Yun-Hi Kim,* and Dae Sung Chung*

2 Supporting information High charge carrier mobility of 2.5 cm 2 V -1 s -1 from water-borne colloid of polymeric semiconductor via smart surfactant engineering Jangwhan Cho, Kwang Hee Cheon, Hyungju Ahn, Kwang Hun Park, Soon-Ki Kwon, Yun-Hi Kim, *, and Dae Sung Chung *, School of Chemical Engineering and Material Science, Chung-Ang University, Seoul , Korea (dchung@cau.ac.kr) Pohang Accelerator Laboratory, San 31 Hyojadong, Namgu, Pohang, Kyung-Buk, , Korea School of Materials Science and Engineering and ERI, Gyeongsang National University, Jinju , Korea Department of Chemistry and ERI, Gyeongsang National University, Jinju , Korea (ykim@gnu.ac.kr)

3 Experimental Section Figure S1 (a) The miniemulsion process for the fabrication of polymer nanoparticle. 2 mg of DPP-SVS was dissolved in 1mL of chloroform and added to water colloids of surfactant (10 mg of C m E n in 1 ml of DI-water) for miniemulsion process. After 1 h of stirring, the chloroform was perfectly evaporated at 70 C. (b) Then the prepared water-borne colloid of polymer nanoparticle was repeatedly washed by means of precipitation and redispersion for more than five times (defined as colloid washing). Colloid washing process was introduced for removal of excess contents of surfactants (c) The device fabrication process including nanoparticle deposition, subsequent annealing and Au deposition, and dipping in ethanol process for removal of extra contents of surfactants (defined as film washing).

4 Colloid synthesis 2 mg of DPP-SVS was dissolved in chloroform and added to water colloids of surfactant (10 mg of C m E n in DI-water) for miniemulsion process. After 1 h of stirring, the chloroform was perfectly evaporated at 70 C. Then the prepared water-borne colloid of polymer nanoparticle was repeatedly washed by means of centrifugation and re-dispersion, for more than five times. Device fabrication A thin film of DPP-SVS was deposited from the colloidal solution by drop-casting and subsequent drying at 70 C. After film washing in ethanol, films were further annealed at 200 C for 10 min. The transistor geometry described in the main text is bottom-contact, bottom-gate with channel W/L ratio of 12. (channel length = 50μm) The top-contact, bottomgate transistor was also tested and the results are summarized in Figure S6. (channel W/L ratio of 10, channel length = 150 μm) The colloid-based films are generally much rougher than general solution-based films. Therefore, in the case of top-contact geometry, the contact resistance between source/drain electrodes and semiconductor is inevitably poor. The topcontact geometry yielded worse transistor performance compared to the bottom-contact case, with charge carrier mobility on the order of 10-1 cm 2 /Vs.

5 Characterization The SEM image was obtained by FE-SEM (Sigma/Carl Zeiss) with a Schottky Field Emitter. The GIXD measurements were performed using the PLS-II 9A U-SAXS beamline at the Pohang Accelerator Laboratory (PAL) in Korea. The X-rays coming from the in-vacuum undulator (IVU) were monochromated (E = kev) using Si(111) double crystals and then focused at the detector position using a K-B focusing mirror system. The horizontal and vertical beam size was 300 (H) μm and 30 (V) μm, respectively. The incidence angle (α i ) was adjusted to 0.13, which is above the critical angle. GIXD patterns were recorded with a 2D CCD detector (Rayonix. SX-165). The diffraction angles were calibrated using pre-calibrated sucrose (Monoclinic, P21) and the sample-to-detector distance was approximately 225 mm. Fourier Transform Infrared Spectroscopy (FT-IR) absorbance peaks were acquired using an FTIR 4700 device (JASCO). The electrical characteristics of the transistors were measured by 4156A Precision semiconductor parameter analyzers (Agilent Technologies).

6 Figure S2. The SEM images of (a) C 12 E 4 -based, (b) C 16 E 10 -based colloid (c) SDS-based colloid, (d) The summary on statistical distribution of particle size.

7 Figure S3. The extracted GIXD profiles along with (a) out-of-plane direction and (b) in-plane direction.

8 Figure S4. FT-IR spectra of colloids followed by colloid and film washing processes. The peak intensity for C O C stretching vibration (δ (1116 cm -1 )) is siginficantly decreased by colloid washing process for both C 12 E 4 and C 16 E 10. At the same time, one can still see the presence of the δ peak, which implies the remaining of some portion of surfactant. This is important for maintaining colloidal stability as we have experimentally observed. Finally, followed by film washing process, one can see clear elimination of surfactant, based on the diminish of δ peak in FT-IR.

9 Figure S5. IR spectrum of chloroform based film.

10 Figure S6. The transfer and output characteristics of PFETs (with top-contact geometry) from (a), (c) C 12 E 4 - based water colloids and (b), (d) C 16 E 10 -based water colloids respectively. All the transfer characteristics were measured at saturation regime.

11 V th μ max (cm 2 V -1 s -1 ) μ (cm 2 V -1 s -1 ) On/Off Current Ratio Chloroform -5.3± ± C 12 E 4 (Bottom contact) C 16 E 10 (Bottom contact) C 12 E 4 (Top contact) C 16 E 10 (Top contact) -8.4± ± ± ± ± ± ± ± SDS 8.2± ± Table S1. Summary on transistor parameters. The statistical data were obtained from 5 independent devices for each fabrication condition.