Alkali metal and alkaline earth metal niobates and tantalates as security feature substances

A security feature, comprising at least one luminescent substance for authentication of a security element, a security paper, a value document or another object, the at least one luminescent substance having a host lattice doped with at least one luminescence activator, wherein the at least one luminescent substance has the general formula AXO3:Z (I)

• wherein:
• A is at least one element selected from the group consisting of alkali metals;
• X is either or both Nb and Ta;
• Z is the luminescence activator, and is at least one element selected from the group consisting of the rare earth metals and transition metals in the oxidation states in which the relevant transition metals are activatable to luminesce;
• and
• wherein the host lattice is additionally doped with at least one element E,
• which:
• acts as a luminescence sensitizer which absorbs energy and transfers it to the luminescent activator and is selected from the transition metal cations, and/or serves for charge equilibration.