Vacuum ultraviolet excitation spectra of lanthanide-doped hexafluoroelpasolites

Vacuum ultraviolet excitation spectra at ∼10K have been recorded for 4f^N ?4f^N?15dtransitions of Cs₂NaYF ₆:Ln³⁺ (Ln = Nd, Sm, Eu, Tb, Ho, Er, Tm). In these high bandgap hosts the lanthanide ions occupy octahedral symmetry sites. The spectra comprise broad, structured bands and in most cases the individual vibronic structure is not resolved. Simulations of the relative intensities and band positions in the spectra have been made by using parameter values from previous studies and/or by employing values from similar systems or estimating trends across the lanthanide series, without data fitting or parameter adjustments. The agreement with experimental results is reasonable except where the luminescent state being monitored is not efficiently populated nonradiatively from the 4f^N-15d state, or where additional bands are present. The latter are readily assigned to charge transfer transitions or the near-excitonic band. Comparison of the spectra has been made with those of other high symmetry lanthanide ion systems. © 2009 IOP Publishing Ltd.