Melt-quenched KCl:Eu2+ films for photostimulated luminescence applications

Using a conventional melt-quenching method, Eu2+-doped KCl films have been prepared. These films yield intense photostimulated luminescence (PSL) with the stimulated excitation maximum shifting to longer wavelengths as compared to the reports on the single-crystal analog. This will be advantageous for image reading by a He-Ne laser or red-emitting diode lasers when used in the PSL applications. Several types of centers have been found. Further, in the electron paramagnetic resonance spectrum, the hyperfine structure due to the Eu2+ centers has been observed to disappear at low temperatures (similar to 5 K). This can be attributed to the formation of complexes by the trapping of defect centers at the Eu2+ site(s). Crystallization effects and paramagnetic centers as well as optical properties of these films are discussed. (C) 1998 American Institute of Physics. [S0021-8979(98)05502-9].