Jahn-Teller effect in the emission and excitation spectra of theSb3+ion inLPO4(L=Sc,Lu,Y)

Luminescence and decay-time measurements are presented for ${\mathrm{Sb}}^{3+}$-doped ${\mathrm{YPO}}_4$, ${\mathrm{LuPO}}_4$, and ${\mathrm{ScPO}}_4$. In these phosphates (with tetragonal zircon structure) only one crystallographic position is available for the $L^{3+}$ions (L=Sc,Lu,Y). The emission of the ${\mathrm{Sb}}^{3+}$ dopant ion at this position consists of two bands, one in the uv region and one in the visible part of the spectrum. The intensity ratio of these bands is strongly temperature dependent. These observations are in agreement with the assumption that a Jahn-Teller effect is acting on the ${}_{}{}^3{}_{}{}^{}\mathrm{P}_1^{}{}_{}{}^{}$ excited state of the ${\mathrm{Sb}}^{3+}$ ion. The presence of a Jahn-Teller distortion in the excited state of the ${\mathrm{Sb}}^{3+}$ ion is confirmed by the shape and temperature dependence of the observed excitation bands. The luminescence behavior of ${\mathrm{Sb}}^{3+}$ in L${\mathrm{PO}}_4$ appears to be similar to the luminescence of ${\mathrm{In}}^{+}$ in CsBr or CsI, which is also governed by a Jahn-Teller effect.