Analysis of the upconversion photoluminescence spectra as a probe of local microstructure in Y2O3/Eu3+ nanotubes under high pressure

Abstract

In situ upconversion photoluminescence measurements of Y₂O₃/Eu³⁺ nanotubes under high pressure were carried out with 632.8 nm laser light excitation. The intensity of ⁵D₀–⁷F_J (J = 0,1,2) transitions increased up to 8.2 GPa due to the enhanced crystal filed with pressure, while above 8.2 GPa, the photoluminescence intensity decreased rapidly. Full width of half maximum (FWHM) of ⁵D₀–⁷F_0,1,2 transitions and I_0–2/I_0–1 of the Eu³⁺ ion luminescence both exhibited obvious changes near 8.2 GPa, indicating the presence of short-range structural changes in the vicinity of the Eu³⁺-ion. The observed changes reflected a disordering of local micro-structure in the vicinity of Eu³⁺-ions resulting from the short-range distortion of YO₆ octahedra under pressure. The luminescence of doped Eu³⁺ ions acted as an effective probe to reveal slight changes in structure and the local crystalline environment of Y₂O₃/Eu³⁺ nanotubes under high pressure.