Site-selective Eu3+ luminescence in Sr2ScLi(B2O5)2

Abstract

New pyroborate Sr₂ScLi(B₂O₅)₂ (SSLBO) doped with Eu³⁺ has been synthesized for the first time by the conventional solid-state method and investigated by spectroscopic means. At 300 K the material exhibits strong orange-red luminescence with a maximum at 613.5 nm. At 5 K the spectra of Eu³⁺ at different Sr sites can be distinguished by using different excitation wavelengths – 395 nm and 405 nm. The O²⁺–Eu³⁺ charge transfer transition in the absorption spectrum has a maximum at 260 nm and 245 nm for 2% and 0.1% Eu³⁺, respectively. The luminescence radiative decay time of Eu³⁺ at Sc, Sr(1) and Sr(2) sites is 4.6 ms, 1.4 ms and 2.6 ms, respectively. The energy transfer resulting from dipole–dipole interactions has been analyzed using the Inokuti–Hirayama model and R₀ is calculated to be 12.7 ± 1.6 Å.