Internal structure of nanoparticles of Al generated by laser ablation in liquid ethanol

TL;DR

This study investigates the internal structure of aluminum nanoparticles produced by laser ablation in ethanol, revealing a layered core-shell structure with a central cavity formed by hydrogen release during solidification.

Contribution

It provides detailed insights into the layered internal structure and formation mechanism of Al nanoparticles synthesized via laser ablation in liquid ethanol.

Findings

Nanoparticles have a core-shell structure with oxide, amorphous, and crystalline layers.

A cavity forms inside the nanoparticle due to hydrogen release during solidification.

The formation process is linked to hydrogen dissolution and release in aluminum.

Abstract

Al NPs are synthesized by laser ablation of a bulk Al target immersed into liquid ethanol saturated with hydrogen at atmospheric pressure. The nanoparticles possess a well-distinguished core-shell structure. High Resolution Transmission Electron Microscopy shows several layers inside the Al nanoparticle: oxide layer, amorphous Al, single crystal Al, and a cavity in the center. Formation of the cavity is attributed to the sharp increase of hydrogen dissolution in Al upon its melting and its eventual release after the solidification.