Luminescence properties of lanthanide doped alkaline earth chlorides under (V)UV and X-ray excitation

The photoluminescence and radioluminescence of Ce3+, Pr3+ and Nd3+ in SrCl2 and BaCl2 are reported and discussed in relation to application as a (fast) scintillator material. The Ce3+ doped materials exhibit the typical fast cerium d–f emission (358, 382 nm in SrCl2 and 350, 375 nm in BaCl2) both under synchrotron and ionizing radiation excitations. A weak afterglow is observed. For Pr3+ a very fast d–f emission is observed in SrCl2 (250, 263, 300 and 328 nm, τ = 13 ns) and BaCl2 (260, 288 and 315 nm, τ = 10 ns), but only under direct f–d excitation. No d–f luminescence is observed for Pr3+ under X-ray excitation. The absence of d–f emission is explained by the energy of the host lattice emission which is too low for energy transfer to the high energy fd states of Pr3+ (230 nm in SrCl2 and 235 nm in BaCl2). The neodymium doped chlorides do not show d–f luminescence.