Nearly Exclusive Growth of Small Diameter Semiconducting Single-Wall Carbon Nanotubes from Organic Chemistry Synthetic End-Cap Molecules

TL;DR

This paper introduces a new metal-free method for synthesizing nearly pure semiconducting single-wall carbon nanotubes with controlled diameters, combining organic chemistry and vapor phase growth, advancing their potential electronic applications.

Contribution

The study presents a novel approach that achieves high-efficiency, metal-free growth of semiconducting SWCNTs with controlled diameters, supported by extensive characterization and theoretical analysis.

Findings

High purity semiconducting SWCNTs achieved without metal catalysts

Strong correlation between SWCNT diameter and electronic properties

Provides insights into growth mechanisms and controlled synthesis

Abstract

The inability to synthesize single-wall carbon nanotubes (SWCNTs) possessing uniform electronic properties and chirality represents the major impediment to their widespread applications. Recently, there is growing interest to explore and synthesize well-defined carbon nanostructures, including fullerenes, short nanotubes, and sidewalls of nanotubes, aiming for controlled synthesis of SWCNTs. One noticeable advantage of such processes is that no metal catalysts are used, and the produced nanotubes will be free of metal contamination. Many of these methods, however, suffer shortcomings of either low yield or poor controllability of nanotube uniformity. Here, we report a brand new approach to achieve high efficiency metal-free growth of nearly pure SWCNT semiconductors, as supported by extensive spectroscopic characterization, electrical transport measurements, and density functional theory calculations. Our strategy combines bottom-up organic chemistry synthesis with vapour phase epitaxy elongation. We identify a strong correlation between the electronic properties of SWCNTs and their diameters in nanotube growth. This study not only provides material platforms for electronic applications of semiconducting SWCNTs, but also contributes to fundamental understanding of the growth mechanism and controlled synthesis of SWCNTs.