Concentration dependence of multipolar mechanisms responsible for Sm ³⁺ → Eu³⁺ Energy Transfer in (Ca _0.97-3x/5.64Sr_0.03)_2.82(VO₄) ₂: 0.12Eu³⁺,xSm³⁺ phosphors

The conventional method (I₀/I - C plot) to determine the multipolar mechanism responsible for the energy transfer between different ions supposed the hypothesis of I₀/I ≫ 1, where I₀ and I are the emission intensity of the energy donor in the absence and presence of the acceptor, respectively. Compared with the conventional method, a modified method for investigation of the multipolar energy transfer proposed in this work demonstrated more precise and valid results. Excluding the prerequisite of I₀1, the concentration-dependent dipole-dipole multipolar interactions for the Sm³⁺ → Eu³⁺ energy transfer were observed based on the fitting results of (I₀I - 1) - C plots for the first time. To clarify how the dominant dipole-dipole mechanism responsible for the Sm³⁺ → Eu³⁺ energy transfer changes from 2-body to 3-body type with the increasing concentration, the possibly involved transitions at high dilution and sufficiently high concentration were respectively proposed from the viewpoint of the conservation of energy. This finding is anticipated to assist scientists in making clear the mechanism leading to the Sm³⁺ → Eu³⁺ energy transfer in Sm ³⁺ and Eu³⁺ co-doped luminescent materials.