A RARE-EARTH PHOSPHOR CONTAINING ONE-DIMENSIONAL CHAINS IDENTIFIED THROUGH COMBINATORIAL METHODS

An unusual luminescent inorganic oxide, Sr,2CeO4,, was identified by p arallel screening techniques from within a combinatorial library of mo re than 25,000 members prepared by automated thin-film synthesis. A bu lk sample of single-phase Sr,2CeO4, was prepared, and its structure, d etermined from powder x-ray diffraction data, reveals one-dimensional chains of edge-sharing CeO6, octahedra, with two terminal oxygen atoms per cerium center, that are isolated from one another by Sr2+ cations . The emission maximum at 485 nanometers appears blue-white and has a quantum yield of 0.48 +/- 0.02. The excited-state lifetime, electron s pin resonance, magnetic susceptibility, and structural data all sugges t that luminescence originates from a ligand-to-metal Ce4+ charge tran sfer.