Preparation and Nanostructure-Control Technologies for Fine Particulate Advanced Materials Using Organized Interfacial Reaction Field

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Emulsion liquid membrane (ELM, w/O/w emulsion) system has been used for separation and concentration of metal ions. In this study, the ELM system was utilized for preparation of fine particulate materials, aiming to control their size,and morphology, by using the micrometer-sized internal water droplets as size-restricted reaction field. The interface between the organic membrane phase and the internal water phase gives hydrophobic,reaction sites for the particles formation, and template effect for particle growth may be expectedPhosphate particles of the selected rare earth metals have been prepared using ELM system. Submicrometer-sized spherical phosphate particles are obtained. Composite LaPO_4 : Ce^<3+>,Tb^<3+> phosphor particles were then prepared, with the resulting particles showing red photoluminescence at 545 nm. Size and morphology-controlled composite Gd-Eu oxalate particles were prepared in ELM system, The oxalate particles thus prepared were calcined in air to obtain Gd_2O … More _3 : Eu^<3+> phosphor particles and in sulfur atmosphere to obtain Gd_2O_2S : Eu^<3+> phosphor particles. These submicrometer-sized spherical phosphor particles showed photoluminescence properties with emission peak at 614 nm for Gd_2O_3 : Eu^<3+> and 628 nm for Gd_2O_2S : Eu^<3+>Upconverting phosphor fine particles (Y_2O_3 : Yb,Er) have been prepared using ELM system. The precursor particles obtained in the VA-10 ELM system were mainly 20-60 nm in size. The Y_2O_3 : Yb,Er particles demonstrated an upconversion emission at 662 nm, by infrared excitation (λ_<ex> = 980 nm) via a two-photon process. Yttrium oxysulfide upconverting phosphor nanoparticles, doped with Yb as a sensitizes and Er (or Ho, Tm) as an activator, have also been prepared, via a solid-gas reaction using precursor oxalate,particles obtained in ELM system. The resulting Y_2O_2S : Yb,Er particles, mainly smaller than 50 nm in diameter, demonstrated green upconversion emission under infrared excitation. Distinct green and blue upconversion emission were also demonstrated by Y_2O_2S : Yb,Ho and Y_2O_2S : Yb,Tm nanoparticles, respectively, under the same, infrared excitation. These upconverting phosphor nanoparticles with different emission under same infrared excitation may be applied to the luminescent reporter materials for the detection of the targeted analyte in multiplexed assays Less