Physico-chemical analysis of white light-emitting Eu, Dy and Cu tri-doped plasmonic glasses synthesized via nanodiamond

Phosphate glasses containing Eu₂O₃, Dy₂O₃ and CuO were melted together with nanodiamond (ND) powder for an assessment of optical and plasmonic properties aiming for the tuning of light-emitting properties towards photonic applications. A thorough evaluation incorporating optical absorption, differential scanning calorimetry, Raman scattering, and photoluminescence (PL) spectroscopy was carried out. The presence of ND allowed for the stabilization of the Cu⁺ ions with blue-emitting character alongside the yellow-emitting Dy³⁺ and red-emitting Eu³⁺ ions thus allowing for attaining the white light-emitting glasses. Further heat treatment within 470–490 °C of the tri-doped glass resulted in the development of the surface plasmon resonance (SPR) characteristic of Cu nanoparticles (NPs). A strong correlation of the optical bandgaps with SPR development is revealed. Further, a novel approach for assessing the activation energy for Cu NP precipitation is proposed linked to the glass transition temperature of the host. Subsequently, the effect of the plasmonic character on the PL properties was evaluated and correlated to the emission color. Correlated color temperature and chromaticity shifts were assessed and analyzed. The study contributes to the fundamental understanding and design of materials for tunable white light-emitting devices and the influence of incorporating plasmonic nanostructures attractive for photonic applications.