Luminescence of LuCl3:Pr3+ under interconfigurational (4f2 → 4f15d1) and band gap excitations

The optical properties of Pr3+ activated LuCl3 under interconfigurational 4f2 → 4f15d1 and band gap (λex = 193 nm; X-ray) excitations have been evaluated. The luminescence of LuCl3:Pr3+ is found to be strongly dependent on the excitation energy: for energies less than the absorption edge of the host, the luminescence of LuCl3:Pr3+ is dominated by the 4f15d1 → 4f2 interconfigurational optical transitions. When luminescence is excited by photons with energies corresponding to the absorption edge or the band gap of the host, the emission spectrum is dominated by the Pr3+ 4f2 → 4f2 intraconfigurational optical transitions. A model to account for the dependence of the emission behavior on the excitation energy is presented. The Cl− → Pr3+ charge transfer band is identified in the excitation spectrum of LuCl3:Pr3+. A comparative study of the Pr3+ luminescence in LuCl3 and LaBr3 is offered.