Photoluminescence and excited states dynamics in PbWO₄:Pr³⁺ crystals

Luminescence and photo-thermally stimulated defects creation processes are studied for a Pr³⁺-doped PbWO₄ crystal at 4.2–400 K under excitation in the band-to-band, exciton, and charge-transfer transitions regions, as well as in the Pr³⁺-related absorption bands. Emission spectra of Pr³⁺ centers depend on the excitation energy, indicating the presence of Pr³⁺ centers of two types. The origin of these centers is discussed. The 2.03–2.06 eV emission, arising from the ¹D₂→³H₄ transitions of Pr³⁺ ions, is found to be effectively excited in a broad intense absorption band peaking at 4.2 K at 3.92 eV. By analogy with some other Pr³⁺-doped compounds, this band is suggested to arise from an electron transfer from an impurity Pr³⁺ ion to the crystal lattice W⁶⁺ or Pb²⁺ ions. The dynamics of the Pr³⁺-related excited states is clarified. In the PbWO₄:Pr crystal studied, the concentration of single oxygen and lead vacancies as traps for electrons and holes is found to be negligible. - Highlights: • Luminescence and defects creation processes in PbWO₄:Pr single crystal investigated. • Existence of Pr³⁺-related luminescence centers of two types revealed. • Charge transfer origin of the intense 3.92 eV absorption/excitation band suggested. • Dynamics of the Pr³⁺-related excited states clarified. • Negligible concentration of single oxygen and lead vacancies in PbWO₄:Pr concluded