Alkaline Earth Metal Zirconate Perovskites MZrO3 (M=Ba2+, Sr2+, Ca2+) Derived from Molecular Precursors and Doped with Eu3+ Ions

Abstract

The effect of alkaline earth metal alkoxides on the protonation of zirconocene dichloride was investigated. This approach enabled the design of compounds with preset molecular structures for generating highâ purity binary metal oxide perovskites MZrO3 (M=Ba2+, Sr2+, Ca2+). Singleâ source molecular precursors [Ba4Zr2(μ6â O)(μ3,η2â OR)8(OR)2(η2â HOR)2(HOR)2Cl4], [Sr4Zr2(μ6â O)(μ3,η2â OR)8(OR)2(HOR)4Cl4], [Ca4Zr2(μ6â O)(μ3,η2â OR)8(OR)2Cl4], and [Ca6Zr2(μ2,η2â OR)12(μâ Cl)2(η2â HOR)4Cl6]â 8â CH2Cl2 were prepared via elimination of the cyclopentadienyl ring from Cp2ZrCl2 as CpH in the presence of M(OR)2 and alcohol ROH (ROH=CH3OCH2CH2OH) as a source of protons. The resulting complexes were characterized by elemental analysis, IR and NMR spectroscopy, and singleâ crystal Xâ ray diffraction. The compounds were then thermally decomposed to MCl2/MZrO3 mixtures. Leaching of MCl2 from the raw powder with deionized water produced highly pure perovskiteâ like oxide particles of 40â 80â nm in size. Luminescence studies on Eu3+â doped MZrO3 revealed that the perovskites are attractive host lattices for potential applications in display technology.Molecular perovskite precursors: A simple, highâ yield synthetic route for the preparation of singleâ source molecular precursors for preparing alkaline earth metal zirconate perovskites MZrO3 (M=Ba, Sr, and Ca; see figure), which were subsequently doped with Eu3+ ions, is presented. The CaZrO3:Eu3+ phosphor showed the highest luminescent intensity and is a highly promising candidate for applications in trichromatic white LEDs.