NLO and white light emission in AuNPs reinforced Li2O–Bi2O3–B2O3–P2O5 glasses: Role of surface plasmonic resonance AuNPs

Abstract

Significant optical nonlinearities in amorphous nanocomposites are essential for developing advanced communications and photonic devices. In this regard, the borate glasses are considered substantial and readily available commercial hosts. The present work demonstrates the white light emission and decay properties in lithium bismuth boro-phosphate glasses reinforced with gold nanoparticles (AuNPs) prepared via melting and quenching technique. Also, their non-linear optical properties are evaluated in the present study. Numerous characterization methods were used to extensively examine the produced glasses, including XRD, HR-TEM, FTIR, XPS, MAS-NMR, DSC, UV–Visible, Photoluminescence, and Z-scan techniques. Following the addition of AuNPs into the glass matrix, an increase in the refractive index and density of the glasses was observed. The amorphous features of the glass sample are disclosed by XRD examination, and DSC research demonstrates the thermal stability of the glasses after the addition of AuNPs, as shown by the rise in Tg values from 459 °C to 486 °C. HR-TEM results reveal the presence of Au metal nanoparticles having a cubic crystal structure with an average size of 14 nm, while XPS analysis shows that the valence of Au is 0, i.e. Au0 or, in other words, the metallic nature of gold in glasses. FTIR, MAS-NMR, and UV–Visible spectral studies demonstrate the substantial modifications in the physical, structural, and optical properties brought about by incorporating AuNPs into the glass matrix. The PL spectra of glasses containing AuNPs show three distinct, sharp emissions at 494, 611, and 738 nm, out of which the blue emission (494 nm) is found to be predominant and has an overall emission in the region of yellow on the CIE diagram with an average lifetime of 12.23 μs. Glasses containing AuNPs have a white light correlated colour temperature (CCT) of 5129 K and CIE chromaticity (x, y) coordinates of (0.346, 0.413). Additionally, we utilized a Z-scan technique to measure the nonlinear absorption coefficient and nonlinear refractive index. Our experimental data show that the values obtained are consistent with the theoretical closed and open aperture values. Based on our findings, it appears that the glasses we prepared have the potential to be utilized in optical switching applications.