Study on the nature of distribution of gold nanoparticles inside the 30Bi₂O₃:70B₂O₃ glass and its impact on optical behaviour

Present study report the influence of distribution of gold nanoparticles on optical properties of bismuth-borate glass. The glass with the composition 30Bi₂O₃:70B₂O₃ was first melted and in this glass matrix, 3 × 10¹¹ number of gold nanoparticles of 10 nm size were incorporated within the glass matrix using three different methods: drop casting method, sandwich method and melt quenching at room temperature. In the very first method, after pouring the liquid glass sample, drops of gold nanoparticles were poured on the top of the melt and placed for annealing. While in sandwich method pouring of first half of the sample followed by pouring of nanoparticles were carried out and then remaining molten glass was poured on it. For melt quenching method, the appropriate weight of chemicals along with gold nanoparticles were mixed and melt was poured at room temperature. These three different methods were adopted to get functional properties in glasses for achieving better optical and electronic properties. The prepared glass matrices were analysed using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESEM), Differential thermal analysis (DTA), UV–Vis–NIR spectroscopy, Fourier transform infrared spectroscopy (FTIR) and Tera-hertz time domain spectroscopy (TDS). XRD confirm the invariability of amorphous nature while FESEM images shows a large variation in the morphology and size of gold nanoparticles inside the glass matrix. The results show that morphology of gold nanoparticles inside the glass is highly dependent on the method adopted for preparation of glass.