Mechanism of luminescent enhancement in Ba₂GdNbO₆:Eu³⁺ perovskite by Li⁺ co-doping

We investigated the Li⁺ ion incorporation in Ba₂GdNbO₆:Eu³⁺ perovskite by atomistic simulations based on energy minimization. We predicted the most probable sites occupied by Eu³⁺ and Li⁺ ions and the related charge-compensation mechanisms involved into these substitutions. The results show that the Eu³⁺ and Li⁺ ions are incorporated mainly at the Gd³⁺ site. In the Li⁺ ion case, there is a charge compensation by Nb_Gd^{• •} antisite. The crystal field parameters and the transition levels for the Eu³⁺ ion in the BGN:Eu³⁺ were calculated with basis on the simulated local symmetry of the Eu³⁺ site. The results show that the mechanism of luminescent properties enhancement is the symmetry distortion induced by the Li⁺ co-doping. - Highlights: • We performed a full defect calculations in Ba₂GdNbO₆ double perovskite. • We modeled with excellent agreement the optical transition of Ba₂GdNbO₆:Eu³⁺ crystal. • We explained the mechanism of luminescent enhancement in Ba₂GdNbO₆:Eu³⁺ perovskite by Li⁺ co-doping