Comparative assessment of the influence of Nd³⁺ and Er³⁺ ions on the thermal quenching of Cu⁺ photoluminescence in phosphate glass

A comparative analysis was carried out on the influence of temperature on the photoluminescence (PL) of Cu⁺ ions in phosphate glass co-doped with either Nd³⁺ or Er³⁺. The data revealed a lower activation energy for the thermal quenching of Cu⁺ PL in the Nd³⁺-containing glass for Cu⁺ sites emitting in resonance with ⁴I_9/2 → ⁴G_5/2 + ²G_7/2 absorption in Nd³⁺ ions. In contrast, a similar evaluation for the Cu⁺/Er³⁺ co-doped glass for Cu⁺ PL in resonance with relevant ⁴I_15/2 → ⁴F_9/2 Er³⁺ absorption produces results comparable to the reference glass without rare earth ions. The current results suggest that the efficient Cu⁺ → Nd³⁺ non-radiative transfer reported supports a deactivation of the resonant Cu⁺ emitting states with increasing temperature.