on bands that appeared around 670, 865 and 980nm were observed in BaFCl:Eu2+ phosphors. They were attributed to F aggregates that were formed by the association of F centers, or by the trapping of electrons at primary Fn+ (n = 2, 3, 4) centers. The growth curves of F and F-aggregated centers were similar, and could be divided into 3 stages. The photo-stimulated luminescence behaviors of F centers and F aggregates were different. The former decayed logarithmically, while the latter decayed hyperbolically. Non-radiative processes related to F aggregates, such as electron migration, accompanied photo-stimulated luminescence.

New Color Centers and Photostimulated Luminescence of BaFCl:Eu2+. W.Chen, Z.Wang, L.Lin, M.Su: Journal of Physics and Chemistry of Solids, 1998, 59[1], 49-53