Luminescence properties of Yb$_{1-x}$Sc$_x$PO$_4$ solid solutions

Luminescence properties of Yb$_{1-x}$Sc$_x$PO$_4$ solid solutions obtained by solid-state reaction were studied. According to the data of XRD analysis the synthesized solid solutions are single phase; the change of crystal lattice parameters is described by Vegard's law. The origin of emission centers was determined under the excitation in UV and VUV spectral regions. It was shown that all solid solutions are characterized by the emission in UV region related to the charge transfer luminescence ($x\ne$ 1) or radiative relaxation of excitons ($x$ = 1). The increased efficiency of energy transfer to the emission centers was shown for solid solutions and attributed to the separation length constrain of the non-thermalized electrons and holes. This effect results in the UV luminescence enhancement in Yb$_{1-x}$Sc$_x$PO$_4$ solid solutions and may be of applied interest for the creation of new phosphors with intense luminescence in the UV range.