One-step fabrication of Au@Al2O3 core-shell nanoparticles by continuous-wave fiber laser ablation of thin gold layer on aluminum surface: Structural and optical properties

Uniform oxide-layer-wrapped plasmonic nanoparticles currently widespread, demand materials in optoelectronic, photonic and catalyst applications. Laser ablation is the most common method to fabricate these materials. In this research, a prompt, eco-friendly and cost-effective method is presented to fabricate novel Au@Al2O3 core-shell nanoparticles. It is a one-step method with continuous-wave fiber laser ablation on an Aluminum (Al) plate coated with gold (Au) nanolayer immersed in ethanol. The core-shell nanoparticles were characterized by transmission electron microscopy, selected area electron diffraction technique, scanning electron microscopy and X-ray diffraction analysis. The shape of the nanoparticles was roughly spherical with an average size of approximately 20 nm. Optical properties of such as absorption spectroscopy in UV/visible/IR ranges were investigated and the calculation of band gap energy of nanoparticles was performed. A combined absorption spectrum containing two significant peaks in UV/visible/IR ranges was signified. The optical band gap was 2.9 eV which is in common and excellent range of semiconductors. This study aimed to evaluate the synthesized core-shell nanoparticle properties by this approach. The fabrication mechanisms of these core-shell nanoparticles are discussed in detail in this paper.