Pressure screening in the interior of primary shells in double-wall carbon nanotubes

TL;DR

This study investigates how double-wall carbon nanotubes respond to pressure using Raman spectroscopy, revealing that outer tubes shield the inner tubes and enhance overall structural stability under high pressure.

Contribution

It provides the first detailed analysis of pressure effects on both inner and outer tubes in double-wall carbon nanotubes using Raman spectroscopy.

Findings

Outer tubes' radial breathing modes decrease rapidly under pressure

Inner tubes' Raman features are less sensitive to pressure

Outer tubes protect inner tubes and improve structural stability

Abstract

The pressure response of double-wall carbon nanotubes has been investigated by means of Raman spectroscopy up to 10 GPa. The intensity of the radial breathing modes of the outer tubes decreases rapidly but remain observable up to 9 GPa, exhibiting a behavior similar (but less pronounced) to that of single-wall carbon nanotubes, which undergo a shape distortion at higher pressures. In addition, the tangential band of the external tubes broadens and decreases in amplitude. The corresponding Raman features of the internal tubes appear to be considerably less sensitive to pressure. All findings lead to the conclusion that the outer tubes act as a protection shield for the inner tubes whereas the latter increase the structural stability of the outer tubes upon pressure application.