Effect of High Pressure in the Luminescence of Pr3+-Doped Ge2O–PbO Glass Containing Au Nanoparticles

Abstract

In this paper, the combined effect of gold nanoparticles and high-pressure densification on the luminescence of Pr3+-doped heavy metal GeO2–PbO photonic glass was investigated. Localized states related to ion-trapped exciton defects, S1 and S2, were observed at 342 and 412 nm before densification. After densification under 7.7 GPa, the structure of the glass host changed irreversibly, as indicated by the infrared spectrum, refractive index, and density measurements. Transmission electron microscopy analyses indicated that the high-pressure densification induced the formation of clusters of gold nanoparticles. The modifications observed in the absorption and luminescence spectra of Pr3+ ions in the VIS–NIR range were associated to the changes in the local field surrounding the Pr3+ ions in the host glass induced by high pressure. For excitation at 445 nm (luminescence from 3P2) and 593 nm (luminescence from 1D2), the combined effect of densification and gold nanoparticles induced an increase in the emissio...