Regulated Dewetting for Patterning Organic Single Crystals with Pure Crystallographic Orientation toward High Performance Field‐Effect Transistors

Abstract

Fabrication of high‐quality organic single‐crystalline semiconductors and their deterministic patterning are core opportunities as well as challenges for large‐scale integration of functional devices with high efficiency and boosted performance. Previous approaches on solution patterning of organic semiconductors have achieved efficient and versatile control of the position, alignment, and size of organic structures. However, the poorly controllable dewetting dynamics of organic solution gives rise to low crystallinity and disordered crystallographic orientation of generated organic architectures that limit their device performance. Here, 1D organic single‐crystal arrays with high crystallinity, strict crystallographic alignment, precise position, tunable, and homogeneous size are fabricated by exploiting an asymmetric‐wettability topographical template. Periodically arranged micropillars with lyophobic sidewalls and lyophilic tops permit the generation of capillary bridges, which enable unidirectional dewetting of organic solution and ordered packing of molecules. The 1D arrays present pure (100) crystallographic orientation with π–π stacking of molecules in the optimal direction of carrier transport, leading to high carrier mobility of 8.7 cm2 V−1 s−1 in the field‐effect transistor measurements. A facile pressure sensor based on the patterned belt arrays is fabricated, exhibiting high sensitivity and long‐term stability.

A Facile Method for the Growth of Organic Semiconductor Single Crystal Arrays on Polymer Dielectric toward Flexible Field‐Effect Transistors

“…The C8‐BTBT crystal array can generate several distinct high‐order spots in the direction of q z (out‐of‐plane) at a given q xy (in‐plane) (Figure e). This is in a sharp contrast to a common polycrystalline organic film, which produces diffuse intensities around the diffraction peaks along the Debye rings . Therefore, it is evident that the C8‐BTBT crystals are essentially single‐crystalline over a large area.…”

High‐Performance Proximity Sensors with Nanogroove‐Template‐Enhanced Extended‐Gate Field‐Effect Transistor Configuration

“…To realize this goal, many strategies have been reported, including improving the crystallinity in semiconducting layer by anti-solvent crystallization, [12] solution epitaxy, [16] off-center spin coating, [8] floating film transfer, [17] solvent vapor annealing [18] and solvent exchange, [19] aligning semiconducting molecules along one specific direction by solution shearing [11] and pre-oriented templates, [20] and optimizing semiconductor/insulator interface by self-assembled monolayer [21] and phase separation between semiconductor/ insulator blends. To realize this goal, many strategies have been reported, including improving the crystallinity in semiconducting layer by anti-solvent crystallization, [12] solution epitaxy, [16] off-center spin coating, [8] floating film transfer, [17] solvent vapor annealing [18] and solvent exchange, [19] aligning semiconducting molecules along one specific direction by solution shearing [11] and pre-oriented templates, [20] and optimizing semiconductor/insulator interface by self-assembled monolayer [21] and phase separation between semiconductor/ insulator blends.…”

“…Highly ordered nanogrooved PTFE templates were fabricated via friction transfer method, that is, a PTFE rod was pressed at a pressure of 1.0 MPa on and then slid against the heated SiO 2 /Si substrate at 140 °C and at a constant rate of 0.5 mm s −1 . According to the reported work on preoriented templates, [15,20,24] electrical performance of organic FET devices is expected to be enhanced by depositing semiconducting layer on this template. The typical atomic force microscope (AFM) morphology of this PTFE template is shown in Figure 1a, in which the PTFE film shows highly aligned nanogroove structure along the friction direction.…”

Precise Patterning of Organic Semiconductor Crystals for Integrated Device Applications

“…By using this method, the OSCCs can also be selectively deposited at the electrode channel regions (Figure g,h), thereby in situ device arrays were achieved. Besides the patterned PR microchannels' template, a patterned Si pillar template developed by Jiang's group was also commonly utilized to fabricate the patterning of OSCCs . Using the patterned Si pillar template, patterned organic single‐crystal arrays of TIPS–pentacene, C8‐BTBT, n ‐alkyl‐substituted tetrachloroperylene diimides (R‐4ClPDIs) with excellent carrier transport performance were obtained.…”