Covalently Functionalized Double-Walled Carbon Nanotubes Combine High Sensitivity and Selectivity in the Electrical Detection of Small Molecules

Abstract

Atom-thick materials such as single-walled carbon nanotubes (SWCNTs) and graphene exhibit ultrahigh sensitivity to chemical perturbation partly because all of the constituent atoms are surface atoms. However, low selectivity due to nonspecific binding on the graphitic surface is a challenging issue to many applications including chemical sensing. Here, we demonstrated simultaneous attainment of high sensitivity and selectivity in thin-film field effect transistors (TFTs) based on outer-wall selectively functionalized double-walled carbon nanotubes (DWCNTs). With carboxylic acid functionalized DWCNT TFTs, we obtained excellent gate modulation (on/off ratio as high as 4000) with relatively high ON currents at a CNT areal density as low as 35 ng/cm(2). The devices displayed an NH(3) sensitivity of 60 nM (or ~1 ppb), which is comparable to small molecule aqueous solution detection using state-of-the-art SWCNT TFT sensors while concomitantly achieving 6000 times higher chemical selectivity toward a variety of amine-containing analyte molecules over that of other small molecules. These results highlight the potential of using covalently functionalized double-walled carbon nanotubes for simultaneous ultrahigh selective and sensitive detection of chemicals and illustrate some of the structural advantages of this double-wall materials strategy to nanoelectronics.

Optical Probing of Local pH and Temperature in Complex Fluids with Covalently Functionalized, Semiconducting Carbon Nanotubes

“…15 Owing to their remarkable photostability, NIR-II emission (which penetrates deeply in biological tissues with minimal autoscattering), and availability of a rich library of structures known as (n, m) chiralities, SWCNTs have attracted considerable research interest in developing innovative biomedical imaging capabilities. [16][17][18][19] However, the chemical selectivity of unfunctionalized nanotubes is generally poor, 20,21 which makes it difficult to differentiate specific chemicals such as H + in the complex chemical environment of biological systems. 3 Herein, we describe the first pH and temperature bi-functional optical nanoprobe based on a new sensing mechanism enabled by infrared defect PL of covalently functionalized semiconducting SWCNTs (f-SWCNTs).…”

Enhancing the Surface Sensitivity and Selectivity: Functionalization of Carbon Nanomaterials

“…The hybrids were previously prepared in dispersion with isoamyl nitrite before drop-casting on top of the interdigitated electrode. Another example employed double-wall carbon nanotubes thin film transistors to detect small molecules at ppb levels [22]. 4-carboxylbenzenediazonium tetrafluoroborate reacted readily with DWCNTs walls to afford hybrids that were highly selective for ammonia compared to a variety of amines.…”

Side-chain effect of organic semiconductors in OFET-based chemical sensors

“…Most of those approaches focused on designing OSC molecules with specific π-conjugated core structures [28,29], bonding or depositing receptors on OSCs [30][31][32], modifying OSC film thickness [33,34], modulating OSC microstructures and morphologies [35,36]. However, the effect of OSC side chain length on OFET chemical sensor performance has not been sufficiently investigated.…”