Researchers at the University of Nebraska–Lincoln, US, have developed a convenient approach for selectively removing m-CNTs from CNT mixtures through laser irradiation in the open air. Due to their metallic nature, m-CNTs were found to react differently to s-CNTs and exhibited induced free electron movement and optical near-field enhancement under external laser irradiation, which can be treated as a high-frequency electromagnetic field.

Heat, oxidize and remove

The m-CNTs were selectively heated, oxidized and removed in the open air under certain laser power and wavelength threshold conditions. This technique demonstrates an easy and convenient approach for fabricating s-CNT-based devices that avoids often tedious further purification steps and separation processes. Thanks to its simplicity, the technique offers a scalable route towards the mass production of s-CNT-based devices and electronics.

A full description of the method can be found in the journal Nanotechnology.