Low-power CW laser-assisted synthesis of plasmonic aluminium nanoparticles using low duty cycle optical chopper

Abstract

This paper reports continuous wave (CW) laser-assisted synthesis of plasmonic aluminium nanoparticles (ANPs) by drastically reducing the laser power density from the existing 105 W/cm2 to 9 W/cm2 using a specially designed ultralow duty cycle chopper. The aluminium target is subjected to laser irradiation by keeping it in a liquid medium maintained at a specific temperature. The effect of chopping frequencies (F), temperatures (T), and surfactant-glucose (C) on the formation of ANPs are investigated through field emission scanning electron microscopic and UV-visible spectroscopic analyses. The energy required for the ejection of ANPs from the target is obtained from the optical source, thermal source, and the molecular collision due to convection current. The purity of the nanoparticle is determined from energy dispersive spectroscopic analysis. The analysis reveals that ANPs of sizes in the range 20–50 nm are formed when F = 30 Hz, T = 60 °C, and C = 18 mg/cc, exhibiting excellent ageing stability. The photoluminescence spectrum, power spectrum, and CIE analyses for the excitations at 350 nm and 390 nm indicate the emission to be blue, suggesting that it is a suitable fluorescence material for UV-plasmonics.