# Nitrogen Doping of Confined Carbyne

## TL;DR

Researchers show how to create nitrogen-doped confined carbyne using specially designed precursors inside carbon nanotubes.

## Contribution

A new method for controlled nitrogen doping of confined carbyne using azafullerene precursors is demonstrated.

## Key findings

- Nitrogen-doped confined carbyne can be synthesized using C59N azafullerenes in nanotubes.
- Resonance Raman spectroscopy reveals distinct spectral changes due to nitrogen doping.
- Charge transfer and mass differences are disentangled as factors affecting the spectra.

## Abstract

Low-dimensional carbon allotropes belong to the most
revolutionary
materials of the most recent decades. Confined carbyne, a linear chain
of sp1-hybridized carbon encapsulated inside a small-diameter
carbon nanotube host, is one extraordinary nanoengineering example.
Inspired by these hybrid structures, we demonstrate the feasibility
to synthesize nitrogen-doped confined carbyne by using azafullerenes
(C59N) encapsulated in nanotubes (“peapods”)
as precursors for the growth of confined carbyne. Resonance Raman
spectroscopy as a site selective local probe has served to identify
the changes in the spectra of nitrogen-doped versus pristine carbon
peapods and confined carbyne. We are able to disentangle frequency
changes due to charge transfer from changes due to the difference
in mass for both the nanotube and the carbyne, where different effects
dominate. This study demonstrates a suitable pathway to achieve controlled
doping of carbyne chains via the use of specifically doped precursors.