Photoluminescence properties of rare earths (Eu3+, Tb3+, Dy3+ and Tm3+) activated NaInW2O8 wolframite host lattice

The photoluminescence (PL) studies on NaIn1−xRExW2O8, with RE=Eu3+, Tb3+, Dy3+ and Tm3+ phases have shown that the relative contribution of the host lattice and of the intra-f–f emission of the activators to the PL varies with the nature of the rare earth cation. In the case of Dy3+ and Tm3+ activators, with yellow and blue emission, respectively, the energy transfer from host to the activator plays a major role. In contrast for Eu3+, with intense red emission, the host absorption is less pronounced and the intra-f–f transitions of the Eu3+ ions play a major role, whereas for Tb3+ intra-f–f transitions are only observed, giving rise to green emission.