Discontinuous Dewetting, Template-Guided Self-Assembly, and Liquid Bridge-Transfer Printing of High-Resolution Single-Walled Carbon Nanotube Lines for Next-Generation Electrodes and Interconnects

Abstract

A template-guided, self-assembly patterning technique called discontinuous dewetting (DD) and liquid bridge transfer (LBT) was applied to successfully pattern single-walled carbon nanotubes (SWCNTs): the first 1D nanomaterials patterned using the technique. The technique could efficiently and simply pattern SWCNTs with 2.5–10 μm resolution using little energy, low temperature (≤90 °C), and low cost and is potentially compatible with roll-to-roll manufacturing. Many variables were investigated to determine successful patterning conditions. The SWCNT patterning technique demonstrates the potential to obtain the often mutually exclusive properties for SWCNT patterning of high resolution and fast throughput/manufacturability. Due to the low concentration attainable in SWCNT dispersions, a preliminary wetting layer and evaporation-driven deposition were required to achieve a uniform and high-density deposition of SWCNTs inside the patterned cavities of a polydimethylsiloxane transfer stamp. The wetting layer allowed for uniform SWCNT deposition inside the cavities by preventing depinning of the SWCNT ink solution in the cavities. The wetting layer also doubled as a release layer during LBT, allowing easy transfer of the SWCNT lines onto hydrophilic substrates. SWCNT lines were patterned with widths down to 2.5 μm, up to centimeter lengths, and a resistivity of 1.9 × 10–3 Ω m without any annealing. This work demonstrates the potential of DD and LBT patterning of SWCNTs for high-resolution R2R printing of cheap and/or flexible next-generation electrodes and interconnects.

Thickness/morphology of functional material patterned by topographical discontinuous dewetting

“…The second contribution to the deposited layer is from the evaporation‐driven flow or convective flow, [ 24 ] similar to what occurs in capillary printing [ 25–28 ] and an effect we encountered when patterning single‐walled carbon nanotubes (SWCNTs) using TDD. [ 4 ] The stretched ink droplet pinned in the microchannels has an increased open surface area that increases evaporation of the ink solvent in the microchannels. As the solvent evaporates, a pressure gradient develops which causes more ink to flow from the main droplet down into the microchannels, carrying more material into the microchannels (Figure 1B).…”

“…Topographical discontinuous dewetting (TDD) is being explored by researchers as an effective template‐guided, self‐assembly, nanoscale/microscale patterning and 2D printing technique for a variety of different functional materials including nanomaterials, [ 1–4 ] polymers, [ 5,6 ] biomaterials, [ 7 ] organic single crystals, [ 1,8–13 ] and perovskite. [ 14 ] Discontinuous dewetting occurs due to variations in the wettability of a substrate surface.…”

“…[ 7 ] The deposited solidified materials in cavities can be transferred to target substrates using liquid bridge transfer, allowing multiple patterned layers fabricated on the same substrate with potential roll‐to‐roll (R2R) compatibility. [ 1,3,4,11 ] The 2D printing technique of TDD is a form of intaglio printing like gravure printing, except uses innovative manipulation of the ink/surface interactions and surface topography to control deposition into the patterned cavities rather than removing excess ink with a doctor blade. An important advantage for TDD is that nanoscale lateral resolution is readily achievable, [ 1 ] unlike gravure printing, [ 19,20 ] with well‐defined line edges.…”

Carbon Nanotube Far Infrared Detectors with High Responsivity and Superior Polarization Selectivity Based on Engineered Optical Antennas

“…In this respect, thermal detectors have an advantage as they can operate in an uncooled mode, although they are generally less sensitive and slower than photonic detectors [ 4 ]. In this situation, new materials with a prominent thermoelectric effect, low specific heat capacity, and high thermal stability become promising candidates for future infrared thermal detectors [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Among those materials, single-wall carbon nanotubes (SWCNT) have attracted great attention due to their unique electrical, optical and thermal properties [ 4 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ].…”

“…In this situation, new materials with a prominent thermoelectric effect, low specific heat capacity, and high thermal stability become promising candidates for future infrared thermal detectors [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 ]. Among those materials, single-wall carbon nanotubes (SWCNT) have attracted great attention due to their unique electrical, optical and thermal properties [ 4 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ]. In particular, SWCNT thin films have been proposed and demonstrated as a potential infrared detection material by a lot of researchers, since they can be made highly uniform and can be diversely doped to form p-n junctions [ 8 , 13 , 14 ].…”