Luminescence and energy transfer properties of Eu3+ and Gd3+ in ZrO2

Red luminescence emission in ZrO2:Gd3+–Eu3+ nanocrystal under 250 nm radiation excitation is achieved. These materials exhibit a tetragonal phase that is retained by the presence of lanthanide ions. Thus, a study of the optical properties as a function of the dopant concentration was been carried out without the deleterious effects of having segregation of other crystalline phases. We analyze the emission and lifetime curves as a function of dopant concentration through a rate equation simulation, finding an excellent fitting. As results, the nonradiative and radiative relaxation constants, as well as a quantitative estimation of the energy transfer processes among Eu3+, Gd3+ and O2− ions are reported for the first time. The proposed model can be extended (or applicable) to explain the fluorescence dynamics in other nanomaterials doped with Eu3+ and Gd3+ under UV excitation.