Luminescence of LuCl 3:Pr 3+ under interconfigurational (4f 2 → 4f 15d 1) and band gap excitations

Abstract

The optical properties of Pr 3+ activated LuCl 3 under interconfigurational 4f 2 → 4f 15d 1 and band gap ( λ ex = 193 nm; X-ray) excitations have been evaluated. The luminescence of LuCl 3:Pr 3+ is found to be strongly dependent on the excitation energy: for energies less than the absorption edge of the host, the luminescence of LuCl 3:Pr 3+ is dominated by the 4f 15d 1 → 4f 2 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 Pr 3+ 4f 2 → 4f 2 intraconfigurational optical transitions. A model to account for the dependence of the emission behavior on the excitation energy is presented. The Cl − → Pr 3+ charge transfer band is identified in the excitation spectrum of LuCl 3:Pr 3+. A comparative study of the Pr 3+ luminescence in LuCl 3 and LaBr 3 is offered.