On the time and temperature dependent photoluminescence of Pr3+ and Gd3+ doped Lu3Al5O12

Highlights: • High quality samples of the solid solution (Lu_2.97-xPr_0.03Gd_x)Al₅O₁₂ were obtained by using a solution combustion method. • Time and temperature dependent spectroscopy of (Lu_2.82Pr_0.03Gd_0,15)Al₅O₁₂ samples shows unique photoluminescence behavior. • The samples show efficient energy transfer from Pr³⁺ to Gd³⁺ at low temperatures. • Energy back transfer from Gd³⁺ to Pr³⁺ is also observed and most efficient at about 275 K. • Back transfer results in unusual decay curves / times of the ⁶P_7/2 → ⁸S_7/2 and ³P₀ → ³H₄ transitions of Gd³⁺ and Pr³⁺. This work concerns the energy transfer between gadolinium and praseodymium hosted by the garnet Lu₃Al₅O₁₂. A solid solution of (Lu_2.97-xPr_0.03Gd_x)Al₅O₁₂ (x = 0.003, 0.006, 0.015, 0.03, 0.06, 0.15, 0.3, 0.6) was synthesized with solution combustion method and investigated with respect to its phase purity, and reflection properties. It turned out that the emission intensity strongly relies on the Gd³⁺ concentration. Furthermore, the energy transfer between praseodymium and gadolinium in (Lu_2.82Pr_0.03Gd_0.15)Al₅O₁₂ was investigated by measuring the time and temperature dependent luminescence from 77 to 500 K of the ⁶P_7/2 $\to$ ⁸S_7/2 and ³P₀ $\to$ ³H₄ transition of Gd³⁺, and Pr³⁺ respectively. It was found that the emission intensity and decay properties of gadolinium and praseodymium highly depend on the temperature.