Metal nanoparticles reveal the organization of single-walled carbon nanotubes in bundles

Abstract

Single-walled carbon nanotubes (SWCNTs) were decorated with metal nanoparticles. Using a complementary analysis with spatially resolved micro-Raman spectroscopy, high resolution transmission electron microscopy, electron diffraction, and tip-enhanced Raman spectroscopy, we show that the SWCNTs form bundles in which smaller diameter SWCNTs are the ones preferentially affected by the presence of Au and Ag nanoparticles. This result is exploited to evaluate the structural organization of SWCNTs with mixed chiralities in bundles, leading us to postulate that smaller diameter SWCNTs surround larger ones. We found that this effect occurs for very distinct scenarios including SWCNTs both in nanometer thin films and in field effect transistor configurations at the wafer-level, suggesting a universal phenomenon for SWCNTs deposited from dispersions.

Raman Spectroscopy Investigation of Laser‐Irradiated Single‐Walled Carbon Nanotube Films

“…Such an analysis is in line with our previous work on the RBM changes for a Au nanoparticle/system that demonstrated selective SERS enhancement of some RBM modes in CNT bundles . The RBM region is shown in Figure with the modes that changed differently marked by arrows.…”

Photosensitive Field‐Effect Transistors Made from Semiconducting Carbon Nanotubes and Non‐Covalently Attached Gold Nanoparticles

“…Rational of our experimental work is a proof‐of‐principle for the wafer‐scalable fabrication of customizable, photosensitive CNT‐FET devices using the formation of nanoconjugates between SWCNTs and Au‐NPs as active material, non‐covalently mediated by pyrene derivatives. In the CNT‐FET approach, the SWCNTs act as channel material and the ideal working point of the sensor device can be adjusted by applying a certain gate field . Non‐covalent interactions are chosen with the aim to keep the electronic structure of the SWCNTs intact .…”

“…Based on the considerations in the introduction, an on‐chip approach of flow chemistry for a non‐covalent functionalization of CNT‐FETs with a pyrene‐alkanethiol derivative as primary and Au‐NPs as secondary functionalization was developed as depicted in the inset of Figure B. Chip‐level functionalization of CNT‐FETs with the pyrene alkanethiols and the gold nanoparticles was done in flow chemistry using a stop‐and‐go microfluidic approach on a 3 × 5 matrix of reticles (footprint 10 × 10 mm 2 each) on the wafer, following a previously reported approach on functionalization of CNT‐FETs on‐chip with oxycarbonyl nitrenes as covalent strategy . Primary functionalization comprised the molecular interlinker, Pyr‐C 12 ‐SH ( X2 ), in chloroform.…”

“…Secondary functionalization was a dispersion of preformed Au‐NPs in triethylene glycol dimethyl ether (triglyme). Details on the functionalization procedure can be found in the Supporting Information, Chapter S1, including the detailed chemical routes and elementary characterization expanding the state of the art based on earlier work (Supporting Information, Section S1.3), electrochemistry (Supporting Information, Section S1.4) and functionalization to achieve the nanoconjugates (Supporting Information, Section S1.5).…”

“…Nanoconjugates (or: hybrids) made from low‐dimensional carbon nanomaterials such as semiconducting single‐walled carbon nanotubes (SWCNTs) and transition metal and/or metal oxide nanoparticles (NPs) have received considerable interest in science and technology as nanoscopic solid‐state building blocks that enable such disruptive nanoelectronic sensor solutions with a high fidelity, sensitivity, and specifity . In such devices, semiconducting SWCNTs can act as a versatile channel material for nanoelectronic transistors (carbon‐nanotube field‐effect transistors: CNT‐FETs) as single or individualized carbon nanotubes (CNTs), aligned as oriented networks, or CNT superstructures in bundles, fibers and ropes, or composite network films . In this work, we outline a method for the fabrication of arrays of CNT‐FETs functionalized with gold nanoparticles as photosensitive or perspectively photochemosensitive field‐effect transistors.…”