Volume 181, 2015

Nanocrystal superlattices that exhibit improved order on heating: an example of inverse melting?

Abstract

Grazing incidence small angle X-ray scattering (GISAXS) measurements reveal that superlattices of 1.7 nm diameter, gold (Au) nanocrystals capped with octadecanethiol become significantly more ordered when heated to moderate temperatures (50–60 °C). This enhancement in order is reversible and the superlattice returns to its initially disordered structure when cooled back to room temperature. Disorder–order transition temperatures were estimated from the GISAXS data using the Hansen–Verlet criterion. Differential scanning calorimetry (DSC) measurements of the superlattices exhibited exotherms (associated with disordering during cooling) and endotherms (associated with ordering during heating) near the transition temperatures. The superlattice transition temperatures also correspond approximately to the melting and solidification points of octadecanethiol. Therefore, it appears that a change in capping ligand packing that occurs upon ligand melting underlies the structural transition of the superlattices. We liken the heat-induced ordering of the superlattices to an inverse melting transition.

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
13 Jan 2015
Accepted
20 Jan 2015
First published
20 Jan 2015

Faraday Discuss., 2015,181, 181-192

Author version available

Nanocrystal superlattices that exhibit improved order on heating: an example of inverse melting?

Y. Yu, A. Jain, A. Guillaussier, V. R. Voggu, T. M. Truskett, Detlef-M. Smilgies and B. A. Korgel, Faraday Discuss., 2015, 181, 181 DOI: 10.1039/C5FD00006H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements