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Ultrafine Y2O3∶Eu powders with two typical morphologies were prepared via double oxalate route. It is found that the feeding manner and reaction procedure play a key role for the product formation of desired morphology. The SEM photograph of Y2O3∶Eu synthesized by precipitating yttrium ion with ammonium oxalate as precipitant in synchronous feeding model shows sheet morphology with plane size ranging from 0.6 to 1.5 μm and sheet size around 50 nm. However, the Y2O3∶Eu synthesized by converting from yttrium hydroxide with oxalate acid displays regular block shape with side size ranging from 300 to 500 nm. The XRD patterns of both intermediates are identical with NH4Y(C2O4)2·H2O. The morphologies of Y2O3∶Eu are consistent with that of their corresponding ammonium yttrium oxalate intermediates analyzed by XRD, indicating that the morphology still remains on calcining. The luminescent spectra of Y2O3∶Eu sheet and block show a strong excitation at 226 nm on their excitation spectra, which is different from that of commercial Y2O3∶Eu.
Ultrafine Y2O3: Eu powders with two typical morphologies were prepared via double oxalate route. It is found that the feeding manner and reaction procedure play a key role for the product formation of the desired morphology. The SEM photograph of Y2O3: Eu synthesized by precipitating yttrium ion with ammonium oxalate as precipitant in synchronous feeding model shows sheet morphology with plane size ranging from 0.6 to 1.5 μm and sheet size around 50 nm. However, the Y2O3: Eu synthesized by converting from yttrium hydroxide with oxalate acid displays regular block shape with side size ranging from 300 to 500 nm. The XRD patterns of both intermediates are identical with NH4Y (C2O4) 2 · H2O. The morphologies of Y2O3: Eu are consistent with that of their corresponding ammonium yttrium oxalate intermediates analyzed by XRD, indicating that the morphology still remains on calcining. The luminescent spectra of Y2O3: Eu sheet and block show a strong excitation at 226 nm on their excitation spec tra, which is different from that of commercial Y2O3: Eu.