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

Abstract

chemical and physical properties, including high mechanical strength, flexi bility, and unique optical and electrical properties. [1,2] The flexibility and stretch ability of carbon nanotubes, combined with their potential for comparable elec trical performance to traditional rigid materials (such as polysilicon and metal oxides) makes them particularly attractive for applications in wearable electronics, prosthetics, and flexible and printed elec tronics. [3] Their capacity for high charge carrier mobilities, [4] combined with solu tion processability, has resulted in the incorporation of SWNTs into photovol taics, [5] field effect transistors, [6] chem ical and biological sensors, [7][8][9] logic circuits, [10,11] and infrared photodetectors for telecommunications. [12] The structural polydispersity of as synthesized SWNTs, both in atomic struc ture and length, remains a major issue hindering widespread applications of these materials into electronics devices. [13] While some synthetic control over the diameter distribution can be achieved, all common techniques produce a dis tribution of chiralities and a mixture of both metallic and semiconducting nano tubes. [14] These mixtures are normally comprised of a ratio of ≈2:1 semiconducting SWNTs (scSWNTs) to metallic SWNTs (mSWNTs), in addition to the retention of impurities such as catalyst particles and amorphous carbon. This disparity in terms of electrical properties is not suitable for organic elec tronic devices, as mSWNTs can act as percolating or directly bridging paths that electrically short SWNT transistors, making the isolation of pure scSWNTs from a raw mixture of the utmost importance. [15] Additionally, SWNTs have poor solu bility and require the introduction of ancillary dispersants to properly exfoliate tube bundles to allow for the fabrication of uniform networks.Significant progress in the dispersion and separation of SWNTs according to electronic character, [16] chirality, [17] diameter, [18] or length [19] has been made over the past two decades. Density gradient ultracentrifugation, [20] gel chromatography, [21] DNA wrapping combined with ion The realization of organic thin film transistors (OTFTs) with performances that support low-cost and large-area fabrication remains an important and challenging topic of investigation. The unique electrical properties of singlewalled carbon nanotubes (SWNTs) make them promising building blocks for next generation electronic devices. Significant advances in the enrichment of semiconducting SWNTs, particularly via π-conjugated polymers for purification and dispersal, have allowed the preparation of high-performance OTFTs on a small scale. The intimate interaction of the conjugated polymer with both SWNTs and the dielectric necessitates the investigation of a variety of conjugated polymer derivatives for device optimization. Here, the preparation of polymer-SWNT composites containing carbazole moieties, a monomer unit that has remained relatively overlooked for the dispersal of large-diameter semiconducting...

Ambipolarity and Air Stability of Silicon Phthalocyanine Organic Thin‐Film Transistors

“…The largest impact on SiPc device performance was the characterization atmosphere, for which we initially evaluated in an evacuated chamber ( P < 0.1 Pa) and then in air at atmospheric pressure after the devices had been removed from vacuum for 5 min. While our previous studies had looked at this comparison for carbon nanotubes wrapped in semiconducting polymers, P‐type small molecules, and conjugated polymers, we have not yet examined this effect on N‐type small molecules, which are particularly sensitive to oxygen. Table 2 summarizes the changes observed for a single set (one substrate) of devices for each material, with Figure showing sample transfer curves under each condition for material 2 .…”

“…For other PDI derivatives, the thickness and morphology of the semiconducting film along with the LUMO level of the molecule have been shown to affect air stability in OTFTs . For carbon nanotube (CNT)‐based OTFTs, the synergistic presence of oxygen and air have been shown to suppress electron conduction, while air has enhanced the P‐type field‐effect mobility compared to low vacuum . These changes in field‐effect properties have not been well studied in many molecular classes for OTFTs, including phthalocyanines, but are vital to understanding their operating limitations and potential for sensing applications.…”

Separation of Semiconducting Carbon Nanotubes Using Conjugated Polymer Wrapping

“…Recently, Rice et al developed a copolymer named PCPF 60 (P15) for sorting SWNTs with large diameter (>1 nm). This novel polymer selected s-SWNTs with a purity greater than 99%, which was confirmed by UV-Vis-IR and Raman spectrum [ 73 ].…”

“…The maximum hole and electron mobilities could achieve 19 and 7 cm 2 /V·s respectively. Additionally, they used a self-assembled monolayer octyltrichlorosilane (OTS) to modify the dielectric surface, which could reduce the operational hysteresis and help to improve the hole and electron mobilities [ 73 , 146 ].…”

Enrichment of large‐diameter semiconducting single‐walled carbon nanotubes by a mixed‐extractor strategy

“…Due to the superiority of large‐diameter s‐SWCNTs, sorting them from commercial arc‐discharge SWCNTs has become a research hotspot . However, due to the strong van der Waals interaction between large‐diameter s‐SWCNTs that is related to the low curvature of the nanotube wall, those s‐SWCNTs are difficult to be dispersed and sorted, especially difficult to realize single‐chirality sorting.…”