Solutal‐Marangoni‐Flow‐Mediated Growth of Patterned Highly Crystalline Organic Semiconductor Thin Film Via Gap‐Controlled Bar Coating

Abstract

Application‐oriented patterned growth of organic semiconductor (OSC) thin films with single crystalline domains is crucial for fabricating sophisticated high‐performance organic‐electronic and optoelectronic devices; however, fabricating these patterned nanometer‐thick crystals in a simple, fast, and effective manner is a difficult task with a roll‐to‐roll printing process. Here, a simple bar‐coating approach to form an array of single‐crystal‐like OSC thin‐film patterns at a rate of a few millimeters per second is introduced. To this end, the processing parameters of a gap‐controlled bar‐coating method is optimized, including coating speed, crystal nucleation, and solution fluidics, which allow a high degree of morphological control of bar‐coated OSC films in an area of several centimeters. In particular, it is demonstrated that the solutal‐Marangoni flow induced by a suitable solvent additive can considerably improve molecular mass transport and induce favorable vertical phase separation. Thus, organic transistors based on the OSC patterns fabricated with the additive‐assisted bar coating show a field‐effect mobility of up to 20 cm2 V−1 s−1 and superior operational stability. The proposed bar coating method will facilitate an industry‐level application of organic electronics.

Molecular Engineering of Printed Semiconducting Blends to Develop Organic Integrated Circuits: Crystallization, Charge Transport, and Device Application Analyses

“…The preferred manufacturing method in this regard is the solution-based printing technology. It is an additive manufacturing method, and the material of interest is manufactured in ink and directly transferred onto the substrate. , This type of manufacturing process has been mainly deployed to produce paper prints, so it has several characteristics that are highly suitable for the requirements of manufacturing OFETs including large-area manufacture, mass production, low unit cost, and applicability to flexible platforms. − …”

Low-Voltage Organic Field-Effect Transistors: Challenges, Progress, and Prospects

“…Klauk et al 89 used a self-assembled monolayer (SAM), n-tetradecylphosphonic acid (TDPA), to reduce the defects at the interface between Al Blending OSCs with insulating polymers has been widely used to reduce the interfacial trap state density. 10,90 When a small-molecule OSC is blended with insulating polymers, OSC-top and dielectric-bottom bilayer structures can be formed via vertical phase separation. The Jie group verified the vertical phase separation behavior between the OSC and polymer by cross-sectional transmission electron microscopy.…”

Microstructural Control of Soluble Acene Crystals for Field-Effect Transistor Gas Sensors

“…Instead of bulky silylethynyl groups, alkyl chains (such as hexyl and octyl) can also be attached to the edges of the acene backbone to enable solution processability ( Figure 1 d,e). 2,7-Dihexyl-dithieno[2,3-d;2′,3′-d′]benzo[1,2-b;4,5-b′]dithiophene (C6-DTBDT) and 2,7-dioctylbenzothieno[2,3-b]benzothiophene (C8-BTBT) are examples that show excellent field-effect mobilities in the application of FETs [ 49 , 67 , 68 , 69 ].…”

“…Here, inducing vertical phase separation in soluble acene/polymer blends is also necessary for fabricating FETs. Readers can read recent review papers focusing on obtaining high field-effect mobility in FETs based on soluble acene/polymer blends [ 17 , 18 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. Instead of introducing strategies for vertical phase separation, this review focuses on introducing key concepts in the microstructural control of soluble acene/polymer blends for high-performance gas sensors.…”