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Luminescence of excitons and Eu 2+ v c – centres in KI:Eu 2+ crystals
Author(s) -
Aceves R.,
Piters T. M.,
Zazubovich S.
Publication year - 2005
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.200440076
Subject(s) - exciton , excited state , atomic physics , luminescence , ion , excitation , absorption (acoustics) , crystal (programming language) , photoluminescence , radiative transfer , electron , chemistry , physics , condensed matter physics , nuclear physics , optics , organic chemistry , quantum mechanics , computer science , programming language
Luminescence characteristics of KI:Eu 2+ crystals are studied at 11.5–300 K under excitation in the 3.0–6.3 eV energy range. Besides the known 2.88 eV emission of Eu 2+ v c – centers, the new emission bands peaking at ∼3.75 eV, ∼3.3 eV, 3.06 eV, and 2.38 eV are found. The bands, located in the 3.1–4.3 eV energy range and strongly distorted due to their overlap with the Eu 2+ v c – absorption bands, are ascribed to the self‐trapped exciton emission. The 3.06 eV and 2.88 eV bands are ascribed to the electronic transitions from two close levels of the splitted T 2g excited state of an Eu 2+ ion. The 2.38 eV emission is ascribed to the radiative decay of an exciton localized near an Eu 2+ ion. It is assumed that the appearance of the self‐trapped exciton emission under excitation in the Eu 2+ ‐related absorption bands is connected with the radiative decay of excitons, which are formed at the recombination of electrons and holes, produced in the crystal as a result of the photostimulated charge transfer from the Eu 2+ ‐perturbed I – states. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)