Host–Guest Molecular Interaction Enabled Separation of Large-Diameter Semiconducting Single-Walled Carbon Nanotubes

Abstract

Semiconducting single-walled carbon nanotubes (s-SWCNTs) with a diameter of around 1.0–1.5 nm, which present bandgaps comparable to silicon, are highly desired for electronic applications. Therefore, the preparation of s-SWCNTs of such diameters has been attracting great attention. The inner surface of SWCNTs has a suitable curvature and large contacting area, which is attractive in host–guest chemistry triggered by electron transfer. Here we reported a strategy of host–guest molecular interaction between SWCNTs and inner clusters with designed size, thus selectively separating s-SWCNTs of expected diameters. When polyoxometalate clusters of ∼1 nm in size were filled in the inner cavities of SWCNTs, s-SWCNTs with diameters concentrated at ∼1.3–1.4 nm were selectively extracted with the purity of ∼98% by a commercially available polyfluorene derivative. The field-effect transistors built from the sorted s-SWCNTs showed a typical behavior of semiconductors. The sorting mechanisms associated with size-dependent electron transfer from nanotubes to inner polyoxometalate were revealed by the spectroscopic and in situ electron microscopic evidence as well as the theoretical calculation. The polyoxometalates with designable size and redox property enable the flexible regulation of interaction between the nanotubes and the clusters, thus tuning the diameter of sorted s-SWCNTs. The present sorting strategy is simple and should be generally feasible in other SWCNT sorting techniques, bringing both great easiness in dispersant design and improved selectivity.

Stabilization of Polyoxometalate Charge Carriers via Redox‐Driven Nanoconfinement in Single‐Walled Carbon Nanotubes

“…As such, there are very few examples describing the successful encapsulation of POMs within single‐walled carbon nanotubes (SWNTs), and these primarily focus on the use of stable, plenary polyoxotungstates. [ 46 , 47 , 48 , 49 ] We recently reported that [PW 12 O 40 ] 3− ( PW 12 ) and [P 2 W 18 O 62 ] 6− ( P 2 W 18 ) spontaneously fill SWNTs under aqueous conditions, a process driven by an in situ redox reaction between the POMs and the SWNTs. [50] The resultant hybrid materials ( PW 12 @SWNT and P 2 W 18 @SWNT respectively, where @ indicates that the POMs are immobilized within the cavities of the SWNTs) exhibited reversible redox chemistry and were stable under harsh conditions and long‐term electrochemical cycling.…”

Stable Doping of Single-Walled Carbon Nanotubes for Flexible Transparent Conductive Films

“…Interactions between PTA and SWCNTs were reported. 56,57 These features make PTA a potential dopant for the SWCNT TCFs.…”

Polyoxometalate steric hindrance driven chirality-selective separation of subnanometer carbon nanotubes

“…We did not observe a notable color change to dark blue aer adding subnanometer CoMo-SWCNTs into {PW 12 } aqueous solution, which is different from the phenomenon observed in previous reports when encapsulating {PW 12 } into large-diameter (1-2 nm) SWCNTs to form heteropoly blues. 70,73 It was further found that there was no obvious shi for the G band of {PW 12 }-out-SWCNTs, compared with that of pristine SWCNTs (Fig. S3 †).…”

“…[70][71][72] We demonstrated that the formation of electron donor-acceptor systems composed of SWCNTs and encapsulated polyoxometalates is effective to modulate the interaction of inter-tubes, thus selectively extracting largediameter semiconducting SWCNTs. 73,74 The adaptability in chemical synthesis provides a wide variety of customized polyoxometalates with tunable redox potentials, which enables precise modulation of the electronic properties of SWCNTs.…”