LUMINESCENCE PROPERTIES OF MN5- EFFECTS OF CHEMICAL AND STRUCTURAL VARIATION( IN A VARIETY OF HOST LATTICES )

The optical spectroscopic properties of Mn5+ doped into ten host latti ces have been studied. The influence of both chemical variation [phosp hates(V), arsenates(V), and vanadates(V)] and structural variation (sp odiosites, apatites, and Li3PO4-type salts) on the luminescence proper ties is studied in detail. By varying the host lattice, the position o f the sharp luminescence band can be varied from 8300 to 8960 cm(-1). Excited state splittings, luminescence lifetimes, and sideband intensi ties are correlated with the geometrical distortion of the MnO43- tetr ahedron. In all the host lattices, the luminescence originates from th e (1)E elicited state at all temperatures. It is essentially unquenche d at room temperature in apatite and Li3PO4-type lattices, whereas in spodiosites up to 90% of the luminescence may be quenched at room temp erature.