Investigation on the gold nanoparticles concentration effects to the optical and structural properties of nanostructure glass

• Main Author: Ho, Reuben Chee Wui
• Format: Thesis
• Language: English
• Published: 2019
• Subjects: QD Chemistry
• Online Access: https://eprints.ums.edu.my/id/eprint/25203/1/Investigation%20on%20the%20gold%20nanoparticles%20concentration%20effects%20to%20the%20optical.pdf; https://eprints.ums.edu.my/id/eprint/25203/

Achieving enhancement of photoluminescence and Raman spectra of glasses containing rare-earth ions and metallic nanoparticles are prerequisite. Many studies only reported the effect of concentration of the nanoparticles on structural and optical properties of the glasses instead of the variation in size and shape of nanoparticles. Thus, the current study aims to investigate effect of concentration of the gold (Au) nanoparticles on structural and optical properties of the glasses. Further, their geometric effect on photoluminescence and Raman enhancement with varying concentration of the gold nanopartides for optimizing photoluminescence and Raman enhancement are addressed. A series of glass with composition of 70TeOr20ZnO-10Na2O-0.SEr2Or(x)Au where x=0.0, 0.1, 0.2, 0.3 and 0.4 mol% were examined with X-ray diffraction (XRD), ultraviolet-visible (UV­Vis) spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), photoluminescence spectroscopy, Fourier Transform Infrared (mR) spectroscopy and Raman spectroscopy. Modification in UV-Vis spectra was observed due to non-bridging oxygen created by gold nanopartides with increasing concentration of gold nanopartides. TEM images verified the presence of non-spherical gold nanopartides. Photoluminescence spectra revealed luminescence enhancement caused by the effect of surface plasmon resonance (SPR) and energy transfer from the gold nanopartides to erbium ions as concentration of the gold nanoparticles was increased up to 0.3 mol%. However, when the concentration of the gold nanoparticles exceeded 0.3 mol%, luminescence quenching occurs due to energy transfer from erbium ions to gold nanoparticles. Amplification of Raman spectra was attributed to the effect of SPR. The concentrations of the gold nanopartides for maximizing photoluminescence and Raman spectra were found to be 0.3 and 0.4 mol%, respectively. Non-spherical shaped nanoparticles were found to optimize photoluminescence and Raman enhancement. The results demonstrated the effect of varying concentration of nanoparticles on the properties of the glasses due to the geometric effect of the nanoparticles especially on the enhancement of photoluminescence and Raman spectra.