Vacuum ultraviolet spectroscopy of Pr3+ in CaAl4O7, LaMgAl11O19 and SrLaAlO4

The vacuum ultraviolet spectroscopy of Pr3+ doped CaAl4O7, LaMgAl11O19 and SrLaAlO4 is reported. It appears that whenever the aluminate host lattice is excited directly, mainly exciton and 4f2–4f2 [3P0] Pr3+ emission are observed. When the excitation energy is lower, Pr3+ ions are excited selectively and 4f5d–4f2 emission dominates. These observations can be explained by assuming that energy transfer from the host lattice to the Pr3+ ion takes place preferentially via an intermediate exciton state with an energy too low to reach the energetic Pr3+ 4f5d excited states.