Tunable luminescence in pyrochlore Lu2Sn2O7:Eu3+ nanoparticles at elevated pressure

Abstract

High pressure study is crucial in chemical, physical and materials sciences for understanding phase transitions, new phase evolution and in designing pressure sensors. Utilizing the high potential of pyrochlore as luminescent sensors and its structural diversity, Lu₂Sn₂O₇:5.0%Eu³⁺ (LSOE) nanoparticles (NPs) have been synthesized using a hydrothermal method and characterized at ambient condition using x-ray diffraction (XRD), Raman spectroscopy and field emission scanning electron microscopy (FESEM). The reduced intensity of hypersensitive electric dipole transitions (⁵D₀→⁷F₂), reduction in average luminescence lifetime, and increase in symmetry around Eu³⁺ has also being observed in the LSOE NPs induced by the applied high pressure. The same is reflected in color tuning from red to orange to yellow on switching pressure from low to medium to high. Lifetime spectroscopy suggests that high pressure causes site-swapping of europium ion from Lu³⁺ to Sn⁴⁺, which triggers change in local symmetry around Eu³⁺. This work will pave a newer way of designing high pressure induced color tunable phosphor, high pressure sensor and need-based site engineering in pyrochlore compounds and their nanomaterials for high pressure applications.