New luminescent materials and high-performance solution-processed oxide thin films.

摘要

Crystals of an incongruent-melting compound, Ba3MgSi 2O8, were grown by the flux method and its structure was determined by single crystal X-ray diffraction methods. Ba3MgSi 2O8 crystallizes in trigonal space group P 3m1 with a = 5.6123(3) A, c = 7.2667(9) A and Z = 1. Eu2+ ions prefer one crystallographic Ba site in the structure and exhibit strong blue emissions at 440 nm. A new series of compounds RE 4Zn4(SiO4)5 (RE=Y, La, Eu, Gd, Tb, Dy, Ho, Er), adopting an unprecedented new structure type, was discovered. Crystals of Y4Zn4(SiO4)5 were grown from a silica-rich eutectic melt and its structure was determined by single-crystal diffraction methods. It crystallizes in tetragonal space group P42/n with cell dimensions a = 9.3289(10) A, c = 9.0509(18) A and Z = 2. Selected photo-luminescence properties of lanthanide ions doped Y4Zn4(SiO4)5 are presented. High-purity MgS:Eu phosphors, exhibiting distinct cubic morphology, high luminescence efficacy, and stability against moisture, were synthesized. Thin films of early transition metal oxides (TiO2, HfO2, Nb2 O5, and V2O5) have been deposited from peroxo-assisted aqueous solutions. The facile decomposition of peroxo ligands upon annealing allows smooth and efficient transformation of the precursors into high-quality films. Therefore, the films exhibit extraordinary performance in advanced optical and electrical devices, such as dielectric mirrors, microcavities, capacitors, and thin-film transistors (TFTs). The control over film thickness to a single-digit nm thickness is also demonstrated through the fabrication of TiO2-AlPO nanolaminates using simple beaker chemistry.