In situ X-ray diffraction observation of two-step fullerene coalescence in carbon peapods

¹ Laboratoire de Physique des Solides, UMR CNRS 8502, Université Paris-Sud - F-91405 Orsay, France, EU
² Institut Laue Langevin - 6 rue Jules Horowitz, B.P. 156, F-38042 Grenoble Cedex 9, France, EU
³ Synchrotron SOLEIL - Saint-Aubin, BP 48, 91192 Gif - sur-Yvette Cedex, France, EU
⁴ Nanosystem Research Institute, National Institute of Advanced Industrial Science and Technology Central 4, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562, Japan

Received: 17 July 2013
Accepted: 11 September 2013

Abstract

We report an in situ X-ray diffraction study of the high-temperature coalescence of C₆₀ and C₇₀ peapods. The monitoring of the structural evolution with time at two successive temperatures (1000 °C and 1200 °C) allows highlighting the occurrence of a two-step process for both peapods samples. The first step of the process, slower for C₇₀ peapods than for C₆₀ ones, is attributed to the transformation of individual molecules into corrugated tubules recalling the fullerenes one-dimensional periodicity. Even after long annealing time at 1000 °C this transformation is found to stagnate, until the temperature is set higher than 1050 °C, where the corrugated tubules evolve into well-formed inner nanotubes.