Effect of Solution Shearing Method on Packing and Disorder of Organic Semiconductor Polymers

Abstract

The solution shearing method has previously been used to tune the molecular packing and crystal thin film morphology of small molecular organic semiconductors (OSCs). Here, we study how the solution shearing method impacts the thin film morphology and causes structural rearrangements of two polymeric OSCs with interdigitated sidechain packing, namely P2TDC17FT4 and PBTTT-C16. The conjugated backbone tilt angle and the thin film morphology of the P2TDC17FT4 polymer were changed by the solution shearing conditions, and an accompanying change in the charge carrier mobility was observed. For PBTTT-C16, the out-of-plane lamellar spacing was increased by solution shearing, due to increased disorder of side chains. The ability to induce structural rearrangement of polymers through solution shearing allows for an easy and alternative method to modify OSC charge transport properties. Introduction:

Macroscopic Alignment of One-Dimensional Conjugated Polymer Nanocrystallites for High-Mobility Organic Field-Effect Transistors

“…Solution shear-coating techniques such as zone casting, 27 doctor blading, 28 strain stretching, 29 and template-guided 8,9,12 have been demonstrated to be effective strategies for the alignment of crystalline domains and polymer chains. Typically, the alignment of polymers or small molecules is achieved through the use of template-guided alignment or confined fluid flows on preengraved substrates.…”

“…8,9,11,12,29,30 While solution shear coating of small molecules has resulted in well-controlled and aligned single-crystalline morphology, 30 it still leads to locally ordered crystalline domains in polymer semiconductors, presumably, in part, due to the large entropy in polymers. 8,9,12,29 Hence, moderate enhancement in the chargecarrier mobility has been observed from polymer thin films prepared by solution shear coating compared to thin films obtained via conventional spin-coating methods. 8,9,11,12,29 For example, a common solution shear-coating approach resulted in a 5-fold enhancement in the carrier mobility of poly[bis-(thiophene-2-yl) tetrathienoacene] (P2TDC17FT4) thin films.…”

Comparison of the Morphology Development of Polymer–Fullerene and Polymer–Polymer Solar Cells during Solution‐Shearing Blade Coating

“…For the in situ study of the structural evolution during the printing process, a solution of P3HT:PCBM 1:1 blends or P3HT:PNDIT 1:1 blends dissolved in chlorobenzene (CB) was solution-sheared on silicon substrates at 35 ˚C [44][45][46] . During the printing, the gap between the hydrophobic treated silicon blade and silicon substrate was fixed at 250 µm.…”

Casting Control of Floating-films into Ribbon-shape Structure by modified Dynamic FTM

“…One of the amicable solutions for this problem is the introduction of macromolecular alignment of CPs. Various methods to prepare oriented thin-films such as friction transfer method [2], mechanical rubbing [3], solution flow [4], capillary action [5], solution shearing [6], slide coating [7] and strain alignment [8] importance for fabricating organic electronic devices by using oriented thin films of CPs in the last one decade, important challenges like simplicity of fabrication process and preparation of multilayer oriented films are yet to be taken into consideration. We have developed a dynamic casting of thin floating-film of CPs on liquid-substrate followed by its transfer on a desired substrate which has been named as dynamic-FTM.…”