Suppress of Concentration Quenching by Site Engineering Concept

Red-emitting RbLa2Ti2TaO10:Eu3+ phosphors were synthesized by a conventional solid-state reaction method, and crystal structure and photoluminescence properties were investigated in the detail. RbLa2Ti2TaO10 has tetragonal structure with a space group of P4/mmm, in which the B-site cations (Ta and Ti) are arranged into non-ordering sequence. The RbLa2Ti2TaO10:Eu3+ phosphors exhibited strong red emission, which is due to the 4f-4f transitions of Eu3+, at excitation wavelength of 396 nm. The concentration quenching phenomena for RbLa2Ti2TaO10:Eu3+ phosphors was investigated using percolation model with two-dimensional interactions among the Eu3+ sites in the host lattice. Both the critical concentration values with the calculation and experiment are estimated to be x = 0.3-0.4, which indicates that the concentration quenching for RbLa2Ti2TaO10:Eu3+ phosphors was due to the energy transfer between the nearest Eu3+ ions in these compounds