Noble metal nanoparticles in glass: A universal pathway towards light modulation

Abstract

Incorporating metallic nanoparticles (NPs) in glass has been of intense artistic interest and scientific and technical enthusiasm, since the localized surface plasmon resonance (LSPR) of metallic nanoparticles enrich glass with light modulation capability, which allows applications from colored glasses to photonic devices. The conventional method of generating metallic NPs in glass comprises two steps: (1) prepare a parent glass containing metal ions over the entire glass volume by the melting-quenching technique; (2) strike the parent glass by post heat-treatment, during which the metal ions are reduced to metal atoms, which subsequently nucleate and grow into metallic NPs. However, to efficiently stimulate the reduction of metal ions in the striking step, a co-doping reducing agent in the glass batch is often used, which limits the glass compositions/types and/or requires toxic and environmentally hazardous chemicals. Initiated by an accidental discovery (Chapter 1), the research presented in this thesis is dedicated to the development of a novel and universal powder reheating technique capable of creating noble metal (Au, Ag, or Au-Ag alloy) NPs in a wide range of glass types/compositions (Chapter 3 and 4), and further employing this technique to produce eco-friendly coloured glass for glass art application (Chapter 5) and to study the modulation of upconversion emissions of Er³⁺ in glass by the in-situ created Au NPs taking into account both near-field and far-field LSPR effects (Chapter 6).