Crystal structure and two types of Eu³⁺-centered emission in Eu³⁺ doped Ca₂V₂O₇

The dependence of Ca₂V₂O₇:Eu³⁺ photoluminescence on the crystal structure was discussed experimentally and theoretically. The important chemical parameters, especially, standard deviation of the bond environmental factor were calculated firstly. Two broad excitation bands with the peaks at 311 and 400 nm covering from 250 to 475 nm and two different types of f–f transition–emission of Eu³⁺ can be found. Detailed discussion demonstrated that two different emission mechanisms exist in Ca₂V₂O₇:Eu³⁺: (1) was from the Eu1³⁺ ions occupying the Ca1 sites and (2) was from the Eu2³⁺ ions in the Ca2 sites. The energy transfer was in two ways: one was from O–V1 charge transfer (CT) to Eu2 and another was from O–V2 CT to Eu1. - Highlights: • The photoluminescence of Ca₂V₂O₇:Eu³⁺ was discussed experimentally and quantitatively. • The important chemical parameters, especially, standard deviation of the bond environmental factor were calculated firstly. • The occupying sites of Eu³⁺ and the energy transfer mechanism were investigated