Jun 29, 2011
Laser-assisted synthesis of gold-silver nanochains
Au-Ag nanoalloys give developers the opportunity to design materials with highly desirable optical characteristics and offer much promise in photonic applications such as optical limiters.
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.
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.
About the author
The research was conducted by scientists based at the Laser Material Processing Laboratory, INLC, Tehran, Iran, which is headed by Prof. Jamshid Sabbaghzadeh, whose research focuses specifically on laser spectroscopy, as well as the design and construction of new classes of solid-state lasers. Parvaneh Jafarkhani, a senior researcher in nanoscience, performed the laser ablation/irradiation process in order to synthesize Au-Ag nanoalloys. Mohammad Javad Torkamany is the group leader and has a strong interest in various laser applications such as laser ablation and surface modification. Siamak Dadras is interested in photobiological applications of nanomaterials, specifically photocatalysis and photosensitization of microorganisms' growth using semiconductor nanoparticles. Ali Chehrghani's field of research is laser optics and he measured the nonlinear properties of the samples by a Z-scan technique.