Self‐Assembled Monolayers as Patterning Tool for Organic Electronic Devices

Abstract

The patterning of functional materials represents a crucial step for the implementation of organic semiconducting materials into functional devices. Classical patterning techniques such as photolithography or shadow masking exhibit certain limitations in terms of choice of materials, processing techniques and feasibility for large area fabrication. The use of self-assembled monolayers (SAMs) as a patterning tool offers a wide variety of opportunities, from the region-selective deposition of active components to guiding the crystallization direction. Here, we discuss general techniques and mechanisms for SAM-based patterning and show that all necessary components for organic electronic devices, i.e., conducting materials, dielectrics, organic semiconductors, and further functional layers can be patterned with the use of self-assembled monolayers. The advantages and limitations, and potential further applications of patterning approaches based on self-assembled monolayers are critically discussed.

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

“…[16,39] The absence of film formation on low surface tension substrates has also been shown when coating at faster speeds, [19,[31][32][33] in the Landau-Levich regime. Solventsurface treatment combinations with higher contact angles lead to unsuccessful coatings, as solvent evaporation at the tip of the meniscus is suppressed, compromising solute supersaturation and precipitation.…”

“…This study has been performed in the evaporative regime characterize by a slow coating speed that precisely balances meniscus retraction by evaporation. [16,39] The absence of film formation on low surface tension substrates has also been shown when coating at faster speeds, [19,[31][32][33] in the Landau-Levich regime. [39] This hints to similar morphological trends in that regime, which would however require further experimental verification.…”

“…Additionally, the combination of high surface energy areas with low surface energy areas has been used on various occasions to guide and pattern thin film formation. [19,[31][32][33] So far, however, clear understanding and guidelines for surface treatment selection are still missing for meniscus-guided coating techniques.…”

Precise Patterning of Organic Semiconductor Crystals for Integrated Device Applications

“…[30,31] In general, the SAM patterns can be generated by various techniques, including shadow masking, microcontact printing, and photolithography. [32] Once the SAM patterns have been constructed, it can be utilized to guide the growth of OSCC on desired locations. Meanwhile, the growth conditions and strategies are also crucial for their morphologies, crystal quality, and molecular packing of the OSCCs, which are important factors for the charge transport in OSCCs.…”

“…The molecular structures of the used SAMs determine the surface properties of the substrate . In general, the SAM patterns can be generated by various techniques, including shadow masking, microcontact printing, and photolithography . Once the SAM patterns have been constructed, it can be utilized to guide the growth of OSCC on desired locations.…”