Scientists from the Iranian National Centre for Laser Science and Technology (INLC) led by Prof. J Sabbaghzadeh, are using a custom-made copper vapour laser (CVL) to prepare Au-Ag nanoalloys. In their work, the researchers appreciate the pioneering approach proposed by Mafune et al. based on the laser re-irradiation of mixed colloidal suspensions of distinct Au and Ag nanoparticles.

Superficial melting

A CVL was identified as an appropriate candidate for the process due to the proximity of its operating wavelengths (510 nm green and 578 nm yellow) to the absorption band of Au nanoparticles, which is cantered about 520 nm.

The group uses UV-vis optical absorption spectroscopy analysis as well as transmission electron microscopy (TEM) to confirm the evolution of the nanoalloys, followed by X-ray photoelectron spectroscopy (XPS) to accurately determine the content of the synthesized material. Absorption behaviour was observed to change totally from saturable absorption (SA) to reverse saturable absorption (RSA).

More details can be found in the journal Nanotechnology.