HOLMIUM-DOPED ANTI-STOKES LUMINESCENT MATERIALS AND SECURITY FEATURES WITH THESE LUMINESCENT MATERIALS

摘要

The invention relates to a luminescent material, particularly for use in security documents, comprised of a host lattice made of rare-earth oxysulfide, which is doped with at least two types of ions. The luminescent material exhibits anti-Stokes luminescence according to Stokes' law when it is irradiated with an excitation radiation. According to the invention, the luminescent material contains two luminescent material constituents, which are co-doped with ytterbium/holmium on the one hand and with ytterbium/erbium on the other. The luminescent material can preferably be used for forming security features.