Ag nanoparticles localised surface plasmon field regulated spectral characteristics of Ho3+-doped phosphate-based glass-ceramic

Abstract

The holmium ion (Ho3+)- activated phosphate-based glass-ceramics with silver nanoparticles (Ag NPs) inclusion were prepared using the standard melt-quenching. The samples were characterised to evaluate the effects of different Ag NPs contents on their structure, microstructure and optical properties. The XRD pattern of the as-quenched samples revealed their glass-ceramic nature. The FTIR and Raman analyses showed the modification of the glass-ceramics network structure due to the embedment of Ag NPs. The TEM and HRTEM images together with the localized surface plasmon resonance (LSPR) absorption bands of the glass-ceramics confirmed the existence of Ag NPs inside the host matrix. The complex impedance analyses of the glass-ceramics suggested the glassy phase dominance in the host network. The photoluminescence (PL) peak intensities were significantly enhanced due to the influence of Ag NPs enabled LSPR effects. The PL decay curve analysis of the glass-ceramics indicated the effect of Ag NPs mediated amplified local electric field and energy transfer from the Ag NPs to Ho3+, a mechanism responsible for the optical traits improvement. The achieved branching ratio and stimulated emission cross-section of the optimum glass-ceramic for the three PL peaks were 73.88% and 46.68 × 10−21 cm2 (green); 83.97% and 41.12 × 10−21 cm2 (red); and 71.40% and 36.95 × 10−21 cm2 (IR). Based on the obtained findings, a structural-optical correlation was established.