Selective Synthesis Combined with Chemical Separation of Single-Walled Carbon Nanotubes for Chirality Selection

TL;DR

This study introduces a bimetallic FeRu catalyst for selective growth of single-walled carbon nanotubes with specific chiralities and diameters, combined with chemical separation techniques to produce highly enriched, single-chirality SWNT samples.

Contribution

The paper presents a novel FeRu catalyst enabling narrow distribution growth of SWNTs and demonstrates effective chemical separation to isolate specific chiralities.

Findings

FeRu catalyst yields predominantly (6,5) SWNTs at 600°C.

At 850°C, produces (8,4), (7,6), and (7,5) SWNTs with narrow distributions.

Chemical separation achieves near-pure (8,4) SWNTs with minimal metallic impurities.

Abstract

Single-walled carbon nanotubes (SWNTs) are potential materials for future nanoelectronics. Since the electronic and optical properties of SWNTs strongly depend on tube diameter and chirality, obtaining SWNTs with narrow (n,m) chirality distribution by selective growth or chemical separation has been an active area of research. Here, we demonstrate that a new, bimetallic FeRu catalyst affords SWNT growth with narrow diameter and chirality distribution in methane CVD. At 600C, methane CVD on FeRu catalyst produced predominantly (6,5) SWNTs according to Uv-vis-NIR absorption and photoluminescence excitation/emission (PLE) spectroscopic characterization. At 850C, the dominant semiconducting species produced are (8,4), (7,6) and (7,5) SWNTs, with much narrower distributions in diameter and chirality than materials grown by other catalysts. Further, we show that narrow-diameter/chirality growth combined with chemical separation by ion exchange chromatography (IEC) greatly facilitate achieving single-(m,n) SWNT samples, as demonstrated by obtaining highly enriched (8,4) SWNTs with near elimination of metallic SWNTs existing in the as-grown material.