Influence of the charge compensating agent on tunable emission of the Ba2MgWO6:Eu3+ double perovskite

Double perovskites have recently received extensive attention due to their attractive photoluminescent properties. Herein, we report how the charge compensating agent influences the structural and spectroscopic properties of investigated ceramic powder. Ba2MgWO6:Eu3+ samples were co-doped with K+ and Li+ ions and obtained by the mechanochemical route. SEM images of the representative sample showed big objects with visible grain boundaries, sticking together. The charge compensator does not affect the character of Eu3+ ions emission which is, in both cases, the emission is composed of magnetic dipole emission from the 5D0 excited level to the 7F1 ground state. However, the experimental results showed that in the sample co-doped with K+ ions a higher number of irregular WO6 groups were created and that they influence the shape and position of the host emission. The mechanism of emission generation from regular and irregular WO6 groups and the interaction between them are discussed in detail. The experimental data are supported by the DFT calculation of the density of states of the samples with Na/K+ co-dopant.