Effects of Solution Annealing on the Crystallinity and Growth of

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Effects of Solution Annealing on the Crystallinity and Growth of Conjugated Polymer Nanowires on a Water Substrate Yong-Jae Kim, Kangho Park, Hee-Tae Jung, Chi Won Ahn, and Hwan-Jin Jeon Cryst. Growth Des., Just Accepted Manuscript • DOI: 10.1021/acs.cgd.7b01378 • Publication Date (Web): 06 Feb 2018 Downloaded from http://pubs.acs.org on February 7, 2018

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Crystal Growth & Design

Effects of Solution Annealing on the Crystallinity and Growth of Conjugated Polymer Nanowires on a Water Substrate

Yong-Jae Kim†, Kangho Park†, Hee-Tae Jung*†, Chi Won Ahn*‡ and Hwan-Jin Jeon*∥ †

Department of Chemical and Biomolecular Engineering (BK-21 PLUS), Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea. ‡ Department of Global Nanotechnology Development, National Nanofab Center at Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea. ∥ Department of Chemical Engineering and Biotechnology, Korea Polytechnic University, 237, Sangidaehak-ro, Siheung-si, Gyeonggi-do 15073, Republic of Korea.

Precisely controlling the growth of crystals of self-assembled conjugated polymers (CPs) in organic thin films remains challenging. Here, we designed a new efficient procedure for controlling the growth of self-assembled CP crystals that involved using a solution annealing process to fabricate organic thin films on the surface of water. In the initial stage of this procedure, seed crystals were formed by administering a drop of a solution of CPs onto the surface of the water and then allowing the solvent to evaporate. Then, when we repeated the solution annealing process several times, we obtained a thin film composed of highly crystalline CP nanowires. By varying the number of times the annealing was repeated, we were able to easily and precisely control the growth and crystallinity of the self-assembled CP crystals in thin films floating on the surface of water.

Figure: Precisely controlled growth of conjugated polymer crystals accomplished using solution annealing.

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Contact details of corresponding authors Hee-Tae Jung* E-mail: [email protected] Korea Advanced Institute of Science and Technology (KAIST) Department of Chemical and Biomolecular Engineering 291, Daehak-ro, Yuseong-gu Daejeon 34141 Republic of Korea. Telephone: +82-42-350-2114

Chi Won Ahn* E-mail: [email protected] National Nanofab Center Department of Global Nanotechnology Development 291, Daehak-ro, Yuseong-gu, Daejeon 34141 Republic of Korea. Telephone: +82-42-366-1789

Hwan-Jin Jeon* E-mail: [email protected] Korea Polytechnic University Department of Chemical Engineering and Biotechnology 237, Sangidaehak-ro, Siheung-si, Gyeonggi-do 15073 Republic of Korea. Telephone: +82-31-8041-0626


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Effects of Solution Annealing on the Crystallinity and Growth of Conjugated Polymer Nanowires on a Water Substrate Yong-Jae Kim†, Kangho Park†, Hee-Tae Jung*†, Chi Won Ahn*‡ and Hwan-Jin Jeon*∥

† Department

of Chemical and Biomolecular Engineering (BK-21 PLUS), Korea Advanced

Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.

‡ Department

of Global Nanotechnology Development, National Nanofab Center at Korea

Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.

∥Department

of Chemical Engineering and Biotechnology, Korea Polytechnic University, 237,

Sangidaehak-ro, Siheung-si, Gyeonggi-do 15073, Republic of Korea. * To whom correspondence should be addressed. *E-mail: [email protected] (H.-T. J), [email protected] (C. W. A), [email protected] (H.-J. J)


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ABSTRACT

Precisely controlling the growth of crystals of self-assembled conjugated polymers (CPs) in organic thin films remains challenging. Here, we designed a new efficient procedure for controlling the growth of self-assembled CP crystals that involved using a solution annealing process to fabricate organic thin films on the surface of water. In the initial stage of this procedure, seed crystals were formed by administering a drop of a solution of CPs onto the surface of the water and then allowing the solvent to evaporate. Then, when we repeated the solution annealing process several times, we obtained a thin film composed of highly crystalline CP nanowires. By varying the number of times the annealing was repeated, we were able to easily and precisely control the growth and crystallinity of the self-assembled CP crystals in thin films floating on the surface of water.


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Self-assembling conjugated polymers (CPs) have attracted increasing attention as promising candidates for challenging potential applications in nanoelectronics, energy devices, optics and sensing devices, owing to the inexpensive solution processing, desired functionalities, ultra-small block size, and flexibility of these polymers.1-4 Poly(3-hexylthiophene) (P3HT) is one of the most intensively studied conjugated polymers due to its good solution processability, strong tendency to crystallize, and high carrier mobility.5-9 The rigid conjugated backbones of P3HT tend to self-assemble into 1D nanowires (NWs) via interchain π–π interactions with benefits for device performance, as relatively high charge-carrier mobility has been shown to result from the highly ordered crystalline domains of the polymer chain backbones in the active layer.10,11 Therefore, to obtain highly ordered 1D crystalline self-assembled P3HT with a precise control of its nanostructures, solution-state self-assembly procedures such as solubility tuning, solution aging, and ultrasonic irradiation have been used lately instead of conventional annealing (thermal or solvent vapor).9-14 Recently, we reported a solution-floating method for the one-pot fabrication of P3HT NW thin films.14 This method was used to induce NW self-assembly and thin film generation simultaneously during evaporation of a good solvent on water serving as the substrate. The growth of the self-assembled P3HT crystals could not be controlled, however, when using this technique because it involved administering a large amount of P3HT solution onto the surface of the water to form a uniform large-area thin film. We therefore here designed a new approach to control the growth of the self-assembled P3HT crystals in a thin film on the surface of water. For this approach, we utilized a solution annealing process similar to the crystallization-driven selfassembly of P3HT, but specifically involving administering a drop of P3HT dissolved in a good solvent onto the water substrate, and then both allowing this drop to spread into a thin film and


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the good solvent to rapidly evaporate. The growth of self-assembled P3HT crystals was controlled by simply changing the number of times this solution annealing process was repeated. Moreover, we found that the morphology of the P3HT thin film was affected by whether toluene or CHCl3 was used as the good solvent for P3HT. The thin film generated in this manner on the surface of the water substrate displayed self-assembled P3HT whose rate of growth and crystallinity could be controlled. Our technique can be widely used for developing nanoarchitectures based on CPs and should find various applications.

Figure 1. Schematic illustration of the precisely controlled growth of P3HT crystals in a thin film on the surface of water accomplished by carrying out multiple rounds of solution annealing. (a) Administration of a drop of the P3HT solution onto the surface of water. (b) A thin film composed of seed crystals was formed as a result of evaporation of the solvent. (c) Repetition of processes (a) and (b) on the preformed P3HT thin film (solution annealing process). (d) and (e) Multiple rounds of the solution annealing process led to the formation of P3HT NWs in the thin film floating on the water surface.


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The way that the solution annealing process precisely controlled the growth of the P3HT crystals is illustrated in Figure 1. First, after administering one drop of P3HT dissolved in a good solvent onto the surface of water and allowing the good solvent to evaporate (Figure 1a−b), nanorod (NR)-shaped crystals were observed to form (Figure 2a), apparently as a result of the self-assembly of well-dissolved P3HT chains. Then, these NR-shaped crystals apparently served as seeds for the growth of well-organized P3HT NWs. We believe the mechanism underlying our procedure to be similar to that including the nucleation of seeds for 1D-crystallization-driven self-assembly of P3HT-based block copolymers.15-17 Driven by an energetically favorable minimization of their contact with water, the self-assembled P3HT crystals floating on the surface of the water aggregated to form thin films. We then, in most of the experiments, repeated this process various numbers of times – where, for each repeat, we administered another drop of the P3HT solution onto the above-formed P3HT thin film on the surface of water and allowed the good solvent to evaporate (Figure 1c, solution annealing process). Repeating the solution annealing process resulted in the growth of preformed seed crystals into short 1D P3HT NW crystals (Figure 1d) and well-organized 1D P3HT NWs (Figure 1e) on the water substrate. Additionally, to optimize concentration of P3HT solution for solution annealing process, we investigated effect of P3HT concentration in toluene on formation of thin film and we concluded that the P3HT solution with 1 mg/mL was optimized condition for solution annealing process due to formation of a lot of seed crystals (Figure S1). Transmission electron microscopy (TEM) was used to visualize the growth of the selfassembled P3HT crystals resulting from repeating the administration of the solution and subsequent solvent evaporation various numbers of times and using two different good solvents (Figure 2). The nanostructured thin films of P3HT were transferred onto a TEM grid directly


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from the surface of water (Figure S2). These TEM images showed that the crystal growth of selfassembled P3HT could be controlled by varying the number of times this solution annealing process was repeated. Overall, seed crystals of P3HT were grown into well-organized 1D P3HT NWs by repeating the solution annealing process four times and using toluene as the good solvent for the P3HT (Figure 2a−c). Specifically, after first administering this P3HT solution onto the water and then allowing the toluene to evaporate, a P3HT thin film composed of seed crystals was formed on the surface of the water (Figure 2a); because the amount of time and of polymer units were insufficient here for the self-assembly of well-organized P3HT NWs. Repeating the solution annealing process twice yielded a lot of NR-shaped P3HT crystals, many of which functioned as seeds for the formation of short P3HT NW crystals (Figure 2b). And repeating the process four times yielded relatively long well-organized 1D P3HT NW crystals with a high area density (Figure 2c), greater than that resulting from only two repeats. The widths of the P3HT seed crystals and NW crystals were measured from the TEM images to be ~ 13 nm.7,18 Similar to TEM analysis, atomic force microscopy (AFM) images presented effect of solution annealing on growth of P3HT NWs (Figure S3). Meanwhile, we also carried out a solvent annealing process because this process differed from the solution annealing process in that it involved carrying out. To compare the effect of the solution annealing process on the behaviors of self-assembly with the effects of the solvent annealing process, we repeated the solvent annealing process (dropping of toluene and subsequent solvent evaporation) on a preformed P3HT thin film. A TEM image of the product of this process showed a P3HT thin film with fibrillar domains and nanoparticles of P3HT (Figure S4). The above results indicated that repeating the solution annealing process on the water surface several times (in order to effect repeated crystallizations during evaporation of solvent) and having enough of the polymer units


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are essential for inducing self-assembly of well-organized P3HT NWs. Without any repeating of the solution annealing process, only small NR-shaped P3HT crystals formed, and served as seeds for the self-assembly of P3HT NWs; then, these seed crystals grew into P3HT NW crystals upon repeating the solution annealing process four times. This result showed that the crystal growth of P3HT was easily controlled from producing NR-shaped crystals to producing well-organized 1D NWs by varying the number of times the solution annealing process was repeated when using toluene as a good solvent for P3HT. To determine the effect of the evaporation rate of the good solvent on the growth of P3HT crystals on the surface of water, we also tested CHCl3 as a good solvent for P3HT. While P3HT tended to self-assemble from toluene, CHCl3 showed different results (Figure 2d−f). Initially, random aggregates of P3HT formed after administering the P3HT dissolved in CHCl3 and then allowing the CHCl3 to evaporate (Figure 2d). These initial random aggregates agglomerated together to form larger P3HT domains after repeating the solution annealing process twice (Figure 2e). P3HT domains formed over an even larger area after repeating the solution annealing process four times (Figure 2f). Although P3HT NWs were generated when using CHCl3 (pink arrows in Figure 2f), the assembled area was limited to only part of the film. The high evaporation rate of CHCl3, compared to that of toluene, probably led to the formation of random aggregates of P3HT when few rounds of the solution annealing process were carried out.14 However, upon increasing the number of times the process was repeated, selfassembled P3HT NWs were formed, albeit in largely aggregated P3HT domains. The formation of P3HT thin films was confirmed by observing a change in the color of the P3HT medium, from orange to purple, after the P3HT solution was administered onto the surface of the water and the good solvent was allowed to evaporate (Figure S5a-c). Upon repeating the solution annealing process five times, the administered P3HT solution formed a droplet due to the P3HT thin film


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covering the surface of the water (Figure S5d and S5e). TEM images of the center and edge of the film showed that there are no morphology differences between P3HT nanowires in the whole film area (Figure S6).

Figure 2. TEM images of the thin film composed of self-assembled P3HT crystals resulting from repeating (see Figure 1) the solution annealing process (i.e., repeating the administration of P3HT solution and evaporation of good solvent [toluene (top) or CHCl3 (bottom)]) not at all (a and d), twice (b and e) and four times (c and f). Different nanomorphologies of the P3HT thin films were observed for these different cases.


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A conformational change of the P3HT polymer from coil−like chains to rod−like chains, and subsequent self-assembly of P3HT into aggregates, has been previously reported to occur in this process, and has been attributed to the formation of interchain π–π interactions during solvent evaporation on the water substrate.19,20 To investigate such a conformational change of P3HT when repeating the solution annealing process, we took UV/Vis photospectrometric measurements of P3HT thin films (Figure 3a and Figure S7). The P3HT thin films formed after repeating the process, whether using toluene or CHCl3, yielded a slightly stronger absorbance peak at about 555 nm and a considerably stronger absorbance shoulder at about 600 nm (lowerenergy bands) than did the P3HT prior to repeating the process, and this strengthening was attributed to the increased occurrence of interchain π–π transitions for P3HT; there was also a sign of molecular ordering of the P3HT polymer when comparing the absorbance spectra.21,22 For the spectra of the P3HT thin films made specifically from toluene, in addition to the two absorbance features at λ = 558 nm and 603 nm, indicating interchain π -π stacking interactions, we also discerned an absorption shoulder at λ = 530 nm corresponding to an intrachain π -π* transition of P3HT (Figure 3a). The intensity of the absorption of the transition (0−0) at 603 nm was observed to increase with more repeats of the solution annealing process due to the decreasing of the excitonic coupling, and we attributed this result to the growth of wellorganized P3HT NWs with more interchain π–π interactions. Increased crystallinity of the P3HT film has been previously shown to result in stronger low-energy bands absorption.22,23 Likewise, for the thin film of P3HT made from CHCl3, the formation of crystalline P3HT NWs after repeating the solution annealing four times was confirmed by the significantly stronger and redshifted absorption shoulder at 603 nm (Figure S7). Meanwhile, on the basis of the Spano


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analysis, the ratio of the absorbance of the 0-0 peak (at λ = 603 nm) to that of the 0-1 peak (at 558 nm) can be used to extract the exciton bandwidth W using the equation23,24

1 0.24 ⁄ 1, 1 0.073 ⁄ where the vibration energy coupled to the electronic transition (Ep) and the refractive index ratio n0−1/n0−0 have been shown to be, respectively, 0.18 eV and 0.97 for P3HT.25 The ratios of the 0-0 absorbance to the 0-1 absorbance and the exciton bandwidth W values for the products of repeating the solution annealing various numbers of times were derived from the absorbance spectra in Figure 3a and are shown in Figure 3b. As shown in Figure 3b, the exciton bandwidth (blue symbols


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Figure 3. (a) Normalized UV absorption spectra (at λ = 530 nm) of the thin films composed of P3HT crystals made using various numbers of repeats and using toluene as the good solvent. (b) The values of the ratio of the 0-0 transition (at λ = 603 nm) to the 0-1 transition (at λ = 558 nm) and the exciton band width W values for various numbers of repeats of the solution annealing. with line in Figure 3b) decreased from 0.08266 to 0.06059 eV as the number of repeats of the annealing was increased. Exciton bandwidth is in general inversely related to exciton conjugation length, and improved backbone planarity promotes longer conjugation lengths.26 Therefore, we concluded that the decreasing exciton bandwidth as the solution annealing was repeated was indicative of high crystallinity of well-organized P3HT NWs in thin films and hence provided strong evidence for growth of P3HT crystals in the thin film during the solution annealing process. In addition, we took grazing-incidence wide-angle x-ray scattering (GIWAXS) measurements to investigate the P3HT crystal growth and the orientation of the thin ﬁlms because we expected that the orientation of each film can be changed as a result of the growth of P3HT crystals from seed crystals to well-organized 1D NWs as a result of repeating the solution annealing process more and more times. 2D GIWAXS images showed strong (100) and (010) peaks at positions along the out-of-plane qz and in-plane qxy axes (Figure S8a-S8c) indicating lamellar and π-π stacking distances of 16.1-16.3 Å and 3.81-3.84 Å, respectively. In particular, repeating the solution annealing more times resulted in increases in the intensities of all of the peaks including of the π−π-stacking-related (010) peak (Figure S8e-S8f). These results provided strong evidence for the enhanced crystallinity of P3HT NWs formed by repeating the solution annealing four times, with this improved crystallinity likely due to growth of P3HT crystals with improved π−π stacking.27 To compare the orientations of each thin film, we set out to analyze normalized in-


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plane line cut profiles along the qxy direction from each WAXS pattern of Figure S8f. 27,28 The normalized line cut profiles (Figure 4a) showed a decrease of the (100) intensity with more repeats of solution annealing. Moreover, the azimuthal full-width half-maximum (FWHM) of the (100) peak, indicative of the mosaicity of crystalline domains within the thin films, was measured and found to decrease with more repeats of solution annealing (Figure 4b). This decrease was attributed to the formation of well-organized NWs adopting more of an edge-on orientation.13,29,30 From the results of the GIWAXS analysis, we confirmed that a change in the orientation occurred as the solution annealing was repeated. This change in orientation provided strong evidence for the effect of the solution annealing process on the evolution of the P3HT crystal growth.


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Figure 4. (a) Normalized line cut profile values along the qxy direction from GIWAXS patterns (see Supporting Information, Figures S8a-S8c) and (b) full-width half-maximum (FWHM) values of the azimuthal angular intensity of (100) peaks from 2D GIWAXS patterns of P3HT thin films for various numbers of repeats of solution annealing. In conclusion, in order to precisely control the crystal growth of self-assembled P3HT, we introduced a solution annealing process on a water substrate that involved carrying out the administration of the P3HT solution and the evaporation of good solvent several times. Interestingly, the number of times that the solution annealing was repeated affected the crystal


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growth of the P3HT regardless of whether toluene or CHCl3 was used as a good solvent for P3HT. More interestingly, we were able to easily control the self-assembly of P3HT from NRshaped seed crystals to well-organized NWs by varying the number of times that the solution annealing was repeated with toluene as the good solvent for P3HT. In particular, TEM observations clearly showed the evolution of P3HT crystals with more repeats of the solution annealing, and UV and x-ray analyses provided strong evidence for the influence of solution annealing on the crystal growth of P3HT on the surface of water. Our solution annealing process presents the possibility to precisely control the growth of self-assembled P3HT crystals and to induce the growth of highly crystalline P3HT NWs on a water substrate for the first time. Finally, we expect our technique to be utilized to develop nano-architectures and grow CP crystals in thin films, and to be considered as a very useful design for fine-tuning the physical properties of nanostructured CPs for next-generation nanoelectronics.

ASSOCIATED CONTENT Supporting Information. The Supporting Information is available free of charge on the ACS Publications website. Experimental details, additional data, X-ray data and references.

AUTHOR INFORMATION Corresponding Author *E-mail: [email protected] (H.-T. J)


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*E-mail: [email protected] (C. W. A) *E-mail: [email protected] (H.-J. J)

Notes The authors declare no competing financial interest.

ACKNOWLEDGMENTS This research was supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (MEST) (NRF-2015K1A4A3047100). This work was also supported by National Research Foundation of Korea (NRF) grants funded by the Korea government (Ministry of

Science,

ICT

and

Future

Planning)

(NRF-2017R1C1B1006807

and

NRF-

2015M3A7B6027973), Korea (MSIP). Also, this work was supported by a National Research Foundation

(NRF)

of

Korea

grant

funded

by

the

Korean

Government

(NRF-

2017H1A2A1046199-Fostering Core Leaders of the Future Basic Science Program/Global Ph.D. Fellowship Program). Experiments at PLS (beamline 9A) were supported in part by MSIP and POSTECH. This research was supported by Nano·Material Technology Development Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Science, ICT and Future Planning.(2009-0082580)

REFERENCES


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(1) Zhang, L.; Zhong, X.; Pavlica, E.; Li, S.; Klekachev, A.; Bratina, G.; Ebbesen, T. W.; Orgiu, E.; Samori, P. A. Nanomesh scaffold for supramolecular nanowire optoelectronic devices. Nat. Nanotech. 2016, 11, 900-906. (2) Zhai, L.; Khondaker, S. I.; Thomas, J.; Shen, C.; McInnis, M. Ordered conjugated polymer nano- and microstructures: Structure control for improved performance of organic electronics. Nano Today, 2014, 9, 705-721. (3) Aronggaowa, B.; Kawasaki, M.; Shimomura, T. Thin, transparent conductive films fabricated from conducting polymer nanofibers. Polym. J. 2013, 45, 819-823. (4) Yamamoto, T. Molecular assembly and properties of polythiophenes. NPG Asia Mater. 2010, 2, 54-60. (5) Chen, J.-T.; Hsu, C.-S. Conjugated polymer nanostructures for organic solar cell applications. Polym. Chem. 2011, 2, 2707. (6) Briseno, A. L.; Mannsfeld, S. C. B.; Jenekhe, S. A.; Bao, Z.; Xia, Y. Introducing organic nanowire transistors. Materials Today, 2008, 11, 38-47. (7) Ihn, K. J.; Moulton, J.; Smith, P. Whiskers of poly(3-alkylthiophene)s. J. Polym. Sci. B Polym. Phys. 1993, 31, 735-742. (8) Kiriy, N.; Jähne, E.; Adler, H.-J.; Schneider, M.; Kiriy, A.; Gorodyska, G.; Minko, S.; Jehnichen, D.; Simon, P.; Fokin, A. A.; Stamm, M. One-dimensional aggregation of regioregular polyalkylthiophenes. Nano Lett. 2003, 3, 707–712. (9) Oh, J. Y.; Shin, M.; Lee, T. I.; Jang, W.S.; Min, Y.; Myoung, J.-M.; Baik, H. K.; Jeong, U. Self-seeded growth of poly(3-hexylthiophene) (P3HT) nanofibrils by a cycle of cooling and heating in solutions. Macromolecules 2012, 45, 7504-7513.


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Page 19 of 26 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60


(10) Lim, J. A.; Liu, F.; Ferdous, S.; Muthukumar, M.; Briseno, A. L. Polymer semiconductor crystals. Materials Today, 2010, 13, 14-24. (11) Tsao, H. N.; Mullen, K. Improving polymer transistor performance via morphology control. Chem. Soc. Rev. 2010, 39, 2372-2386. (12) Kleinhenz, N.; Persson, N.; Xue, Z.; Chu, P. H.; Wang, G.; Yuan, Z.; McBride, M. A.; Choi, D.; Grover, M. A.; Reichmanis, E. Ordering of poly(3-hexylthiophene) in solutions and films: effects of fiber length and grain boundaries on anisotropy and mobility. Chem. Mater. 2016, 28, 3905-3913. (13) Zhao, K.; Khan, H. U.; Li, R.; Hu, H.; Amassian, A. Carrier transport enhancement in conjugated polymers through interfacial self-assembly of solution-state aggregates. ACS Appl. Mater. Interfaces 2016, 8, 19649-19657. (14) Kim, Y.-J.; Jung, H.-T.; Ahn, C. W.; Jeon. H.-J. Simultaneously induced self-assembly of poly(3-hexylthiophene) (P3HT) nanowires and thin-film fabrication via solution-floating method on a water substrate. Adv. Mater. Interf. 2017, 201700342. (15) Qian, J.; Li, X.; Lunn, D. J.; Gwyther, J.; Hudson, Z. M.; Kynaston, E.; Rupar, P. A.; Winnik, M. A.; Manners, I. Uniform, high aspect ratio fiber-like micelles and block co-micelles with a crystalline π-conjugated polythiophene core by self-seeding. J. Am. Chem. Soc. 2014, 136, 4121-4124. (16) Gwyther, J.; Gilroy, J. B.; Rupar, P. A.; Lunn, D. J.; Kynaston, E.; Patra, S. K.; Whittell, G. R.; Winnik, M. A.; Manners, I. Dimensional control of block copolymer nanofibers with a πconjugated core: crystallization-driven Solution self-assembly of amphiphilic poly(3hexylthiophene)-b-poly(2-vinylpyridine). Chem. Eur. J. 2013, 19, 9186-9197.


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(17) Kim, Y.-J.; Cho, C.-H.; Paek, K.; Jo, M.; Park, M. K.; Lee, N.-E.; Kim, Y. J.; Kim, B. J.; Lee, E. Precise control of quantum dot location within the P3HT-b-P2VP/QD nanowires formed by crystallization-driven 1D growth of hybrid dimeric seeds. J. Am. Chem. Soc. 2014, 136, 27672774. (18) Liu, J.; Arif, M.; Zou, J.; Khondaker, S. I.; Zhai, L. Controlling poly(3-hexylthiophene) crystal dimension: nanowhiskers and nanoribbons. Macromolecules, 2009, 42, 9390-9393. (19) Shimizu, H.; Yamada, M.; Wada, R.; Okabe, M. Preparation and characterization of water self-dispersible poly(3-hexylthiophene) particles. Polym. J. 2007, 40, 33-36. (20) Cativo, M. H. M.; Kim, D. K.; Riggleman, R. A.; Yager, K. G.; Nonnenmann, S. S.; Chao, H.; Bonnell, D. A.; Black, C. T.; Kagan, C. R.; Park, S.-J. Air–liquid interfacial self-assembly of conjugated block copolymers into ordered nanowire arrays. ACS Nano 2014, 8, 12755–12762. (21) Park, Y. D.; Lee, H. S.; Choi, Y. J.; Kwak, D.; Cho, J. H.; Lee, S.; Cho, K. Solubilityinduced ordered polythiophene precursors for high-performance organic thin-film transistors. Adv. Funct. Mater. 2009, 19, 1200-1206. (22) Chang, M.; Choi, D.; Egap, E. Macroscopic alignment of one-dimensional conjugated polymer nanocrystallites for high-mobility organic field-effect transistors. ACS Appl. Mater. Interfaces 2016, 8, 13484-13491. (23) Clark, J.; Chang, J. F.; Spano, F. C.; Friend, R. H.; Silva, C. Determining exciton bandwidth and film microstructure in polythiophene films using linear absorption spectroscopy. Appl. Phys. Lett. 2009, 94, 163306. (24) Spano, F. C. Modeling disorder in polymer aggregates: the optical spectroscopy of regioregular poly(3-hexylthiophene) thin films. J. Chem. Phys. 2005, 122, 234701.


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(25) Malik, S.; Nandi, A. K. Thermodynamic and structural investigation of thermoreversible poly(3-dodecyl thiophene) gels in the three isomers of xylene. J. Phys. Chem. B 2004, 108, 597– 604. (26) Masri, Z.; Ruseckas, A.; Emelianova, E. V.; Wang, L.; Bansal, A. K.; Matheson, A.; Lemke, H. T.; Nielsen, M. M.; Nguyen, H.; Coulembier, O.; Dubois, P.; Beljonne, D.; Samuel, I. D. W. Molecular weight dependence of exciton diffusion in poly(3-hexylthiophene). Adv. Energy Mater. 2013, 3, 1445–1453. (27) Sirringhaus, H.; Brown, P. J.; Friend, R. H.; Nielsen, M. M.; Bechgaard, K.; Lange-veldVoss, B. M. W.; Spiering, A. J. H.; Janssen, R. A. J.; Meijer, E. W.; Herwig P.; de Leeuw, D. M. Two-dimensional charge transport in self-organized, high-mobility conjugated polymers. Nature 1999, 401, 685-688. (28) Chen, C.-Y.; Tsao, C.-S.; Huang, Y.-C.; Liu, H.-W.; Chiu, W.-Y.; Chuang, C.-M.; Jeng, U.S.; Su, C.-J.; Wu, W.-R.; Su, F.-W.; Wang, L. Mechanism and control of the structural evolution of a polymer solar cell from a bulk heterojunction to a thermally unstable hierarchical structure. Nanoscale, 2013, 5, 7629–7638. (29) DeLongchamp, D.; Kline, J.; Fischer, D. A.; Richter, L. J.; Toney, M. F. Molecular characterization of organic electronic films. Adv. Mater. 2011, 23, 319-337. (30) Verploegen, E.; Mondal, R.; Bettinger, C. J.; Sok, S.; Toney, M. F.; Bao, Z. Effects of thermal annealing upon the morphology of polymer–fullerene blends. Adv. Funct. Mater. 2010, 20, 3519-3529.


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For Table of Contents Use Only Effects of Solution Annealing on the Crystallinity and Growth of Conjugated Polymer Nanowires on a Water Substrate Yong-Jae Kim1, Kangho Park1, Hee-Tae Jung*1, Chi Won Ahn*2 and Hwan-Jin Jeon*3 1

Department of Chemical and Biomolecular Engineering (BK-21 PLUS), Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea. 2

Department of Global Nanotechnology Development, National Nanofab Center at Korea Advanced Institute of Science and Technology (KAIST), 291, Daehak-ro, Yuseong-gu, Daejeon 34141, Republic of Korea.

3

Department of Chemical Engineering and Biotechnology, Korea Polytechnic University, 237, Sangidaehak-ro, Siheung-si, Gyeonggi-do 15073, Republic of Korea.

SYNOPSIS Precisely controlled growth of P3HT crystals was achieved on a water substrate by repeating the solution annealing process several times. Repeating this annealing process a few times led to the growth of self-assembled P3HT crystals from seed to well-organized nanowire on fabricated organic thin films. The growth of the crystals was demonstrated by the results obtained from TEM, UV absorption and x-ray scattering investigations.


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Effects of Solution Annealing on the Crystallinity and Growth of

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