Optical spectroscopy and luminescence quenching of image

Optical spectroscopy of image doped with image using ultraviolet and visible light excitation is reported. image host excitation and emission and 4f–5d excitation and emission of image are observed. An empirical model based on crystal field splitting was used to estimate the energy of the highest 4f–5d excitation band. The crystal field splitting and centroid shift were compared to those of image and image. Temperature dependence of X-ray excited luminescence spectra shows thermal quenching, whereas that of the decay curve of image emission excited at the lowest 5d band of image does not indicate the presence of quenching of image emission for temperature below 625 K. The quenching in image therefore occurs before the 5d image emission takes place.