Analysis of Energy Transfer and Concentration Quenching in Sm3+-Activated Borate GdB3O6 Phosphors by Means of Fluorescence Dynamics

This article reports on the optical properties of Sm³⁺-activated GdB₃O₆ phosphors based on the measurement of their photoluminescence spectra and luminescence decay curves. Energy transfer from Gd³⁺ to Sm³⁺ and the concentration quenching of the Sm³⁺ ion emission are investigated. From the photoluminescence spectra and decay curves, the energy transfer from Gd³⁺ to Sm³⁺ is confirmed. The concentration quenching of the Sm³⁺ ion emission can be ascribed to resonant cross-relaxation. The interaction between the Sm³⁺ ions is derived of the electric dipole–dipole type through fitting the data with the Inokuti-Hirayama model. The critical distances and energy transfer microparameter for the transfer processes are given. The decay curves of Sm³⁺⁴G_5/2 level exhibiting a buildup and decay process also confirm the energy transfer from Gd³⁺ to Sm³⁺ and between Sm³⁺ ions.