The X-ray absorption fine structure and photoluminescence measurements were combined to analyze the structure of Cu centers in SrS:Cu thin-film and powder samples. It was found that all of the data could be understood on the basis of a model involving 3 kinds of Cu center: dumb-bell type Cu–Cu complexes (the dominant centers), substitutional centers (CuSr) and interstitial centers (Cui). The bond lengths in the dumb-bell centers were determined from the X-ray absorption data. Two characteristic emission bands peaking at about 460 and 510nm were attributed to Cui and dumb-bell centers, respectively. The dependences of the emission spectrum on temperature and Cu concentration were explained by a dissociation–association reaction of the type Cu–Cu ↔ CuSr+Cui, assuming center-dependent excitation efficiencies and thermal quenching rates.

The Configuration of Cu Centers in Electroluminescent SrS:Cu Phosphors - an X-ray Absorption Fine Structure and Optical Study. D.Wruck, R.Boyn, M.Wienecke, F.Henneberger, U.Troppenz, B.Hüttl, W.Bohne, B.Reinhold, H.E.Mahnke: Journal of Applied Physics, 2002, 91[5], 2847-52