A Direct Writing Approach for Organic Semiconductor Single‐Crystal Patterns with Unique Orientation

Abstract

Organic semiconductor single‐crystal (OSSC) patterns with precisely controlled orientation are of great significance to the integrated fabrication of devices with high and uniform performance. However, it is still challenging to achieve purely oriented OSSC patterns due to the complex nucleation and growth process of OSSCs. Here, a general direct writing approach is presented to readily obtain high‐quality OSSC patterns with unique orientation. In specific, a direct writing method is demonstrated wherein the microscale meniscus is manipulated, which makes it possible to precisely control the nucleation and growth process of the OSSC because of its comparable size to the crystal nuclei. The resulting OSSC patterns are highly crystalline and purely oriented, in which each ribbon crystal shows a deviation angle of 33° to the printing direction. The mechanism of orientation purification is revealed experimentally and theoretically, and the results show that the TCL deformation caused by the difference in wettability and adhesive force, as well as the asymmetry of fluid concentration distribution, are the key factors leading to the selective deposition and unique orientation. Moreover, organic field‐effect transistors (OFETs) and polarization‐sensitive photodetectors are prepared based on the OSSC patterns with unique orientation, which exhibit higher device performance compared to the non‐purely oriented crystal‐based OFETs.

A no-hysteresis TIPS–pentacene:polystyrene blend-based organic field effect transistor by extruded direct ink writing and the application in a resistive load inverter circuit

“…It can be seen that the OFET with drop casted TIPS–pentacene:PS film has the mobility of 1.00 cm −2 V −1 s −1 , threshold voltage of 21.86 V, and I ON / I OFF ratio of 3.3 × 10 3 . Compared to drop casted TIPS–pentacene:PS blend OSC in this work and spun-cast, as well as the blade-coated and inkjet printed devices from other groups, as shown in Table S1 (ESI†), 10,43–47 the OFET with the extrusion-based DIW printed TIPS–pentacene:PS blend demonstrates threshold voltage of 1.46 V, which is much better than the other techniques. In addition, there is negligible hysteresis, indicating very low charge trap density at the phase separated interface.…”

Directed Assembly of Nanomaterials for Making Nanoscale Devices and Structures: Mechanisms and Applications

“…Because of this limitation, a surface functionalized with a hydrophobic self-assembled monolayer (SAM) can be used instead of a photoresist as a template. The SAM provides a high contrast in wettability between the pattern and the surrounding substrate area and allows confinement of assembly solely within the patterned hydrophilic areas. ,, The detailed process of functionalizing the substrate with a SAM can be found in previously published articles. − Currently, the fast fluidic assembly process is mostly used to fabricate patterns with dimensions in millimeter or submillimeter scale. − This is because the viscous force from the substrate diminishes with the dimensions of the pattern. , Li et al enhanced the surface adhesion force through photoirradiation and chemical polarization treatments to the substrate. As a result, a submicrometer (600 nm) resolution was achieved (Figure b).…”

“… 297 − 299 Currently, the fast fluidic assembly process is mostly used to fabricate patterns with dimensions in millimeter or submillimeter scale. 300 − 302 This is because the viscous force from the substrate diminishes with the dimensions of the pattern. 303 , 304 Li et al 303 enhanced the surface adhesion force through photoirradiation and chemical polarization treatments to the substrate.…”

Complementary Inverter Based on n‐Type and p‐Type OFETs with the Same Ambipolar Organic Semiconductor and ITO S/D Electrodes

“…Therefore, in principle, both n-type and p-type OFETs can be obtained simultaneously by combining the WF adjustment of ITO S/D electrodes and organic ambipolar materials. Moreover, various solution based methods have been developed to prepare organic thin films, [34][35][36][37][38][39][40][41][42] such as solution shearing, inkjet printing, dip-coating, spray printing, bar-coating, screen printing, and direct-write printing. Among these methods, bar-coating is considered a simple, efficient, and low-cost method to fabricate electronic devices in industry.…”