Bi-doped compounds recently became the subject of an extensive research due to their possible applications as scintillator and phosphor materials. The oxides co-doped with Bi³⁺ and trivalent rare-earth ions were proposed as prospective phosphors for white light-emitting diodes and quantum cutting down-converting materials applicable for enhancement of silicon solar cells. Luminescence characteristics of different Bi³⁺-doped materials were found to be strongly different and ascribed to electronic transitions from the excited levels of a Bi³⁺ ion to its ground state, charge-transfer transitions, Bi³⁺ dimers or clusters, radiative decay of Bi³⁺-related localized or trapped excitons, etc. In this review, we compare the characteristics of the Bi³⁺-related luminescence in various compounds; discuss the possible origin of the corresponding luminescence centers as well as the processes resulting in their luminescence; consider the phenomenological models proposed to describe the excited-state dynamics of the Bi³⁺-related centers and determine the structure and parameters of their relaxed excited states; address an influence of different interactions (e.g., spin-orbit, electron-phonon, hyperfine) as well as the Bi³⁺ ion charge and volume compensating defects on the luminescence characteristics. The Bi-related luminescence arising from lower charge states (namely, Bi²⁺, Bi⁺, Bi⁰) is also reviewed.

The impact of 230-MeV Xe¹³² ion irradiation on the structural, optical, and luminescent properties of YAG:Ce single crystals is investigated over a fluence range of 10¹¹–10¹⁴ ions/cm². Optical absorption; cathodo-, X-ray, and photoluminescence; and X-ray diffraction are employed to analyze radiation-induced changes. Irradiation leads to the formation of Frenkel (F, F⁺) and antisite defects and attenuates Ce³⁺ emission (via enhanced nonradiative processes and Ce³⁺ → Ce⁴⁺ recharging). A redistribution between the fast and slow components of the Ce³⁺-emission is considered. Excitation spectra show the suppression of exciton-related emission bands, as well as a shift of the excitation onset due to increased lattice disorder. XRD data confirm partial amorphization and a high level of local lattice disordering, both increasing with irradiation fluence. These findings provide insight into radiation-induced processes in YAG:Ce, which are relevant for its application in radiation–hard scintillation detectors.

A systematic study of photothermally stimulated defects creation processes is carried out by the thermally stimulated luminescence (TSL) method for a large number of undoped and doped PbWO₄ crystals under irradiation at 80–180 K in the 3.4–4.3 eV energy range. The activation energy E_a for the regular exciton state disintegration is found to be ∼0.1 eV. For defect-related states disintegration, E_a varies in the crystals studied from 0.03 to 0.36 eV. The origin of the defect-related states is discussed. The conclusion is made that not only a release of charge carriers but also charge transfer processes take place under UV irradiation of PbWO₄ crystals.