Effect of Ar Gas Pressure on LSPR Property of Au Nanoparticles: Comparison of Experimental and Theoretical Studies.

Yasemin Gündoğdu,Hamdi Şükür Kiliç,Serap Yiğit Gezgin,Abdullah Kepceoğlu,Bouchta Sahraoui,Anna Zawadzka,Sidiki Zongo

doi:10.3390/nano10061071

Abstract

In this study, the thin films were produced by using pulsed laser deposition (PLD) technique from gold (Au) nanoparticles deposited on two kinds of substrates under different argon (Ar) gas pressure. Microscope glass slides and silicon (100) wafers were used as amorphous and crystal substrates. The films were deposited under 2 × 10−3 mbar, 1 × 10−2 mbar, 2 × 10−2 mbar argon (Ar) ambient gas pressure. Effect of the background gas pressure on the plasma plume of the ablated Au nanoparticles was investigated in details. Morphology of Au nanoparticle thin films was investigated by means of atomic force microscopy (AFM) technique. Absorption spectra of Au nanoparticles were examined by using UV-Vis spectrometry. Extinction spectra of Au nanoparticles were calculated by using metallic nano particles boundary element method (MNPBEM) simulation programme. Both experimental spectra and simulation data for Au nanoparticles were obtained and compared in this work. It was concluded that they are also in good agreement with literature data. The measurements and the simulation results showed that localized surface plasmon resonance (LSPR) peaks for Au nanoparticles were located in the near infrared region (NIR) because of the larger size of the disk-like shape of Au nanoparticles, and the near-field coupling between Au nanoparticles. It was demonstrated that as the ambient gas (Ar) pressure was increased, the size and the density of Au nanoparticles on the substrate were decreased and the LSPR peak shifts toward the short wavelength region in the spectrum. This shift has been explained by the changes in the morphology of produced thin films.

Highlights

Metal nanoparticles with featured size in the range 1–100 nm have unusual chemical and physical properties as compared with its bulk form [1]
Au nanoparticle thin films have been deposited by using pulsed laser deposition (PLD) system at different Ar ambient gas pressures and the tunability of localized surface plasmon resonance (LSPR) peak position has been described
According to several investigations found in the literature, the LSPR peaks of the PLD-grown Au plasmonic nanoparticles are generally located in the near infrared region (NIR) region of the spectrum

Summary

Introduction

Metal nanoparticles with featured size in the range 1–100 nm have unusual chemical and physical properties as compared with its bulk form [1]. We showed that LSPR band of Au nanoparticles can be controlled and shifted toward the near infrared (NIR) region of the spectrum These optical changes were attributed to the morphologic characteristics of nanoparticles such as the comparatively large size, disk-like geometrical shape of Au nanoparticle, and the near-field coupling between Au nanoparticles [5,9,10,12,14,15]. It is possible to obtain semiconductor layer absorbing in the desired region of the solar spectrum by controlling the size of the nanoparticles to adjust the position of LSPR peaks This application gives us a strong expectation that high conversion efficiency of photovoltaic devices will be achieved [18]. We showed that the experimental results are consistent with the simulation ones

Experimental

Simulation Results

Conclusions