Influence of the Surface Treatment on the Solution Coating of Single‐Crystalline Organic Thin‐Films

Abstract

and others [10,22,23] show high potential to achieve next generation high performance thin films. These techniques rely on the creation of a moving meniscus front, where enhanced evaporation at the tip of the meniscus leads to the precipitation of the organic solute onto the advancing single-crystalline thin film. As it defines meniscus shape, the wetting behavior of the solution on the substrate strongly impacts film formation.Typically, self-assembled monolayers are used to modify the surface energy of substrates [24] as well as to reduce their surface defect density [25,26] and control the carrier density. Several studies show that for evaporated thin films of organic semiconductors, self-assembled monolayer treatments affect both film morphology and electrical characteristics. [27][28][29] Generally, treatments with low surface energy are preferred for evaporation of organic thin films as they typically lead to larger grain sizes and good passivation of the dielectric surface. [27,29] For meniscus-guided coating

Influence of Solute Concentration on Meniscus‐Guided Coating of Highly Crystalline Organic Thin Films

“…In the evaporative regime, the coating speed is chosen close to the equilibrium meniscus receding speed governed by solvent evaporation. In previous works on this regime, we defined guidelines to select the optimum coating speed and substrate surface treatment as a function of solvent, organic semiconductor, and substrate temperature. Pursuing further this clarification effort, here, we address the impact of solute concentration c s on the formation of highly crystalline organic thin films by meniscus‐guided coating techniques in the evaporative regime.…”

“…These films are typically processed on inert substrates using meniscus‐guided coating techniques such as solution shearing, dip coating, zone casting, and others . These solution coating techniques drag a droplet of solution laterally across a highly lyophilic surface, resulting in a shallow meniscus front at the edge of the receding solution drop. Enhanced solvent evaporation at the edge of this meniscus leads to supersaturation of the solution and precipitation of the organic solute onto the advancing crystalline thin film.…”

Understanding the Meniscus‐Guided Coating Parameters in Organic Field‐Effect‐Transistor Fabrications

“…The corresponding T b and γ values are listed in Table 1 . We paid particular attention to the surface tension difference between substrate and solvent as it will determine the formation of the meniscus‐line and level of supersaturation and thus crystal growth . As shown in Figure S1 in the Supporting Information, the γ of phenyltrichlorosilane (PTS) treated substrate is 43.35 mN m −1 and it is higher than all the solvents being used (Table ).…”

Marangoni Effect‐Controlled Growth of Oriented Film for High Performance C8‐BTBT Transistors

“…The transfer curves of the OFETs are shown in Figure . The threshold voltages, I ON / I OFF ratios, subthreshold swing and three methods of calculating mobility: the highest initial mobilities in the saturation regime, μ sat , their corresponding effective mobilities, μ eff, and the mobilities based on the average slope, μ avg‐Vg are listed in Table 1 .…”

“…To explore the intrinsic mobility, the method of non‐ V G ‐dependent mobility was also used to analyze whether the mobility approached the intrinsic mobility . When this method was adopted, the highest transistor average effective mobility (μ avg‐vg ) was 30.7 cm 2 V −1 s −1 (Figure S5, Supporting Information).…”