Alignment of Organic Semiconductor Microstripes by Two‐Phase Dip‐Coating

Abstract

A new solution‐processing method, termed as two‐phase dip‐coating, is proposed for the alignment of organic semiconductors, with the assistance of a surfactant. The resultant ultrathin aligned microstripes for both n‐ and p‐type conjugated molecules show an electron mobility of 0.12 cm2 V‐1 s‐1 and a hole mobility of 0.16 cm2 V‐1 s‐1, respectively.

Wafer‐Scale Precise Patterning of Organic Single‐Crystal Nanowire Arrays via a Photolithography‐Assisted Spin‐Coating Method

“…Moreover, the growth time is independent of the substrate area, because all of the NW arrays in the substrate started growing at the same time when the solution was spin‐coated uniformly on the substrate. This finding is in sharp contrast to other previously reported methods, such as inkjet printing, evaporation‐induced self‐assembly, zone casting, and dip coating, in which growth times entirely rely on the substrate area and usually in the range of several tens of minutes to several hours. The high efficiency of the photolithography‐assisted growth method is expected to be highly useful in practical applications.…”

“…Despite these advantages, the scale‐up of SMOSC nanostructures for technological applications is difficult because the growth orientation and location of SMOSC nanostructures are usually stochastic in nature. Various methods such as dip coating, solution shearing, and evaporation‐induced self‐assembly have been developed to create continuous SMOSC nanostructure arrays. These methods are capable of roughly controlling their directional growth and alignment, but high‐throughput precise positioning and patterning of SMOSC nanostructures in the desired locations remains difficult to achieve.…”

“…In previously reported solution‐based approaches, such as zone casting, dip coating, and solution‐sheared deposition, the solution moves toward a specific direction, thus the NW arrays are formed only in a particular direction. By contrast, the photolithography‐assisted spin‐coating method enables the fabrication of complex patterns in any desired directions, which can replicate the pattern shapes of the photoresist with high accuracy.…”

Marangoni‐Effect‐Assisted Bar‐Coating Method for High‐Quality Organic Crystals with Compressive and Tensile Strains

“…Forming an ultrathin layer of organic semiconductor with large grain size and less defects is normally desired to achieve a high mobility. Solution deposition is often adapted because of less strict requirements for the fabrication and better crystallinity of the deposited films than thermal evaporated ones . Among various solution processes, the bar‐coating methods have the advantages of high deposition rate, roll‐to‐roll compatibility, and excellent uniformity over a large area.…”

A New Dip Coating Method to Obtain Large‐Surface Coatings with a Minimum of Solution

“…In the “mono‐phasic” configuration, a much larger volume of solution would have been required to coat the same surface. Dip coating in two phase systems, one phase being water and the other being an organic solution, has been recently reported to prepare aligned microstripes of semiconductor . This was possible because of the good affinity of both polar and nonpolar phases with the substrate surface.…”