One-Step Sub-10 μm Patterning of Carbon-Nanotube Thin Films for Transparent Conductor Applications

Abstract

We propose a technique for one-step micropatterning of as-grown carbon-nanotube films on a plastic substrate with sub-10 μm resolution on the basis of the dry transfer process. By utilizing this technique, we demonstrated the novel high-performance flexible carbon-nanotube transparent conductive film with a microgrid structure, which enabled improvement of the performance over the trade-off between the sheet resistance and transmittance of a conventional uniform carbon-nanotube film. The sheet resistance was reduced by 46% at its maximum by adding the microgrid, leading to a value of 53 Ω/sq at a transmittance of 80%. We also demonstrated easy fabrication of multitouch projected capacitive sensors with 12 × 12 electrodes. The technique is quite promising for energy-saving production of transparent conductor devices with 100% material utilization.

All‐Carbon Thin‐Film Transistors as a Step Towards Flexible and Transparent Electronics

“…[91] Copyright 2016, Elsevier. d) Approximate distribution of the optoelectrical performance of CNT TCFs prepared by dry-drawing, [57] solution processing, [63,77] gas filtration, [82][83][84] and gas filtration with grids, [90,91] in comparison with that of ITO, [93,94] Ag nanowire [93,94] and PEDOT:PSS TCFs. [94] The transmittance data is given for a wavelength of 550 nm.…”

“…[89] The optoelectrical performance of CNT TCFs produced by floating-catalyst CVD can be further improved by introducing a microgrid structure to the TCFs, which overcomes the tradeoff between sheet resistance and transmittance of conventional CNT TCFs. [90] Ohno et al developed a technique to fabricate CNT TCFs with sub-10 μm patterns based on the dry transfer process, using a patterned membrane filter on which photoresist patterns were formed, as shown in Figure 1c. The TCFs with the microgrid structure had a sheet resistance of 53 Ω sq -1 at a transmission of 80%.…”

“…In this sample the resistance was reduced by a maximum of 46%, compared to that of the usual uniform TCFs, even though the quality of CNTs is same. [90] When individual CNTs were used to assembly the TCFs with microgrid structure, the optoelectrical performance of flexible CNT TCFs was greatly improved with a sheet resistance up to 69 Ω sq -1 at 97% transmittance. [91,92] These results further demonstrate that the control and elimination of bundling are essential for optimizing the performance of CNT TCFs.…”

“…High-performance and uniform single-wall CNT TCFs can be produced using continuous synthesis by floating catalyst CVD [79] along with the gas-filtration technique. [80][81][82][83][84]90,91] Such TCFs can be easily R2R transferred from a filter to various substrates. This strategy will be promising for the manufacture of low-cost, flexible and transparent electrodes at non-vacuum and room-temperature conditions.…”

Highly transparent conductive ITO/Ag/ITO trilayer films deposited by RF sputtering at room temperature

“…Next, high optical transmittance in the visual spectrum is another important characteristic of a high-quality TCF. Due to the great advance of experimental exploration, a large variety of TCFs, including traditional metal oxides, 2-7 graphene, 8 carbon nanotubes, 9 metal nanostructures, [10][11][12][13][14] and so on, have been successfully fabricated and widely applied in optoelectronic devices. Among these TCFs, tin-doped indium oxide (ITO) dominates the market in high-end optoelectronics because of its excellent electrical and optical properties.…”