On‐Chip Chemical Self‐Assembly of Semiconducting Single‐Walled Carbon Nanotubes (SWNTs): Toward Robust and Scale Invariant SWNTs Transistors

Abstract

In this paper, the fabrication of carbon nanotubes field effect transistors by chemical self-assembly of semiconducting single walled carbon nanotubes (s-SWNTs) on prepatterned substrates is demonstrated. Polyfluorenes derivatives have been demonstrated to be effective in selecting s-SWNTs from raw mixtures. In this work the authors functionalized the polymer with side chains containing thiols, to obtain chemical self-assembly of the selected s-SWNTs on substrates with prepatterned gold electrodes. The authors show that the full side functionalization of the conjugated polymer with thiol groups partially disrupts the s-SWNTs selection, with the presence of metallic tubes in the dispersion. However, the authors determine that the selectivity can be recovered either by tuning the number of thiol groups in the polymer, or by modulating the polymer/SWNTs proportions. As demonstrated by optical and electrical measurements, the polymer containing 2.5% of thiol groups gives the best s-SWNT purity. Field-effect transistors with various channel lengths, using networks of SWNTs and individual tubes, are fabricated by direct chemical self-assembly of the SWNTs/thiolated-polyfluorenes on substrates with lithographically defined electrodes. The network devices show superior performance (mobility up to 24 cm V s ), while SWNTs devices based on individual tubes show an unprecedented (100%) yield for working devices. Importantly, the SWNTs assembled by mean of the thiol groups are stably anchored to the substrate and are resistant to external perturbation as sonication in organic solvents.

Polycarbazole‐Sorted Semiconducting Single‐Walled Carbon Nanotubes for Incorporation into Organic Thin Film Transistors

“…While our average and highest mobilities are on par or higher than many polymer-SWNT random network OTFTs reported in the literature, [59,64,67,83,84] our mobilities are one to two orders of magnitude lower than record SWNT OTFTs prepared with highly aligned SWNTs. While our average and highest mobilities are on par or higher than many polymer-SWNT random network OTFTs reported in the literature, [59,64,67,83,84] our mobilities are one to two orders of magnitude lower than record SWNT OTFTs prepared with highly aligned SWNTs.…”

Recent Advances in Ambipolar Transistors for Functional Applications

“…Thus, diverse alignment methods have been developed including external‐force driven approaches such as DEP, liquid flow and self‐assembly strategies for instance Langmuir‐Schaefer deposition and Langmuir–Blodgett assembly . In addition, it is worth mentioning that the functionalized polymers can be utilized to anchor the SWNTs on electrodes during the deposition, which makes SWNTs tend to self‐align . Recently, Derenskyi et al exploited blade‐coating technique to align nanotube networks in semiconducting channel and the manufactured transistors exhibited unprecedentedly large on/off ratio (about 10 8 ) (Figure b) …”

Accessing MHz Operation at 2 V with Field‐Effect Transistors Based on Printed Polymers on Plastic

“…[12,13] Given the limited carrier mobility and the coarse resolution of printing tools, printed organic electronics has struggled to deliver the challenging performances required to enable wireless capabilities. [21,22] However such high performances are either achieved by resorting to conventional micro and nanofabrication techniques (i.e., e-beam lithography, chemical vapor deposition, sputtering, and thermal evaporation), or pose scaling and processing issues (placing of high-quality monolayers of 2D materials, [23] alignment of carbon nanotubes, [24][25][26][27] and process temperatures compatible with cheap plastic substrates for high-quality metal-oxide layers [28,29] ).It is therefore highly desirable to further develop printed and flexible organic electronics in order to achieve high-frequency operation. [21,22] However such high performances are either achieved by resorting to conventional micro and nanofabrication techniques (i.e., e-beam lithography, chemical vapor deposition, sputtering, and thermal evaporation), or pose scaling and processing issues (placing of high-quality monolayers of 2D materials, [23] alignment of carbon nanotubes, [24][25][26][27] and process temperatures compatible with cheap plastic substrates for high-quality metal-oxide layers [28,29] ).…”