Synthesis and Characterization of Silver-Gold Bimetallic Nanoparticles for Random Lasing

Wan Zakiah Wan Ismail,Judith M Dawes

doi:10.3390/nano12040607

Wan Zakiah Wan Ismail, Judith M Dawes

Open Access

https://doi.org/10.3390/nano12040607

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Abstract

We developed rough silver-gold bimetallic nanoparticles for random lasing. Silver nanoparticles were synthesized based on a citrate-reduction method and the gold (III) chloride trihydrate was added to produce bimetallic nanoparticles. Gold atoms were deposited on the surface of the silver (Ag) through galvanic replacement reactions after the solution was stored at room temperature. Sample characterization and a spectrometry experiment were performed where bimetallic nanoparticles with nanogaps and the extinction of the nanoparticles were observed. The aim of this research is to synthesize nanoparticles for random dye laser in a weakly scattering regime. The novel bimetallic nanoparticles were added to Rhodamine 640 solution to produce random lasing. We found that random dye laser with bimetallic nanoparticles produced spectral narrowing and lasing threshold compared to random dye laser with silver nanoparticles. We attribute that to the localized surface plasmon effects which increase local electromagnetic field to provide sufficient optical gain for random lasing. The rough surface of bimetallic nanoparticles also contributes to the properties of random lasing. Thus, we suggest that the rough bimetallic nanoparticles can be used to develop random lasers.

Highlights

Nowadays, research on metal nanoparticles is broad, comprising of many fields such as sensing [1], laser bioprinting [2] and random lasers [3,4,5]
When Au atoms are deposited on the surface of the silver, the silver plasmon resonance peak shifts from 410 nm to 560 nm and broadens, leading to a more effective overlap of the spectra of bimetallic nanoparticles with the pump laser wavelength, absorption, and fluorescence of Rhodamine 640 (Rh640)
Rough silver-gold bimetallic nanoparticles were created for random laser

Summary

Introduction

Research on metal nanoparticles is broad, comprising of many fields such as sensing [1], laser bioprinting [2] and random lasers [3,4,5]. There are two common techniques used to prepare metallic nanoparticles; (1) Reduction of the metal cations and (2) Disassembling larger objects by grinding or laser ablation [6]. Bimetallic nanoparticles were used to produce random lasers [5] where gold-silver bimetallic nanowires were fabricated to provide strong feedback. In this random laser, Rhodamine 6G (Rh6G) dye was used because it can absorb maximum excitation light

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