Y and Cd co-doped ZnO nanopowders were prepared via chemical precipitation method in order to modify the band gap and increase the luminescent intensity. The structures and optical properties of the as-synthesized sam...Y and Cd co-doped ZnO nanopowders were prepared via chemical precipitation method in order to modify the band gap and increase the luminescent intensity. The structures and optical properties of the as-synthesized samples were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and photoluminescence （PL）. The effects of Y and Cd ions on the optical properties of the samples were studied. Doping of Y into ZnO evidently increases the intensity of UV emission, or co-doping of Y and Cd enhances the UV emission, narrows the band gap of ZnO and hence red shifts the UV emission at the same time. Therefore, Y and Cd co-doped ZnO nanopowders exhibit an intense violet emission in the room temperature PL spectrum, which could be a potential candidate material for optoelectronic applications.展开更多
Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a genera...Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a general,surfactantfree,large-scale synthesis approach for Fe3 O4 spheres.Herein,we developed a facile scalable solvothermal method in the absence of surfactants to produce Fe3 O4 spheres with the yield of 5.1 g,which present tunable sizes from 107 to 450 nm by modulated molar ratio of Fe3+/COO-in the solution.Particularly,it is observed that the reactants undergo a redox process,composed of a precipitation-dissolution equilibrium combined with a coordination reaction(termed as RPC),to the final product based on the LaMer model.It is worth noting that the generation of di-carboxyl group and its coordination with iron cations determine the formation of Fe3 O4 spheres.This work not only offers a strategy to precisely tailor the particle size in scalable synthesis process,but also gives the insight on the role of dihydric alcohol in the formation mechanism of Fe3 O4 spheres in the absence of surfactants.展开更多
基金Project(2010CB631001) supported by the National Basic Research Program of ChinaProject(20121098) supported by the Foundation from of Key Laboratory of Preparation and Applications of Environmental Friendly Materials,Ministry of Education,ChinaProject supported by Graduate Innovation Fund of Jilin University,China
文摘Y and Cd co-doped ZnO nanopowders were prepared via chemical precipitation method in order to modify the band gap and increase the luminescent intensity. The structures and optical properties of the as-synthesized samples were characterized by X-ray diffraction （XRD）, X-ray photoelectron spectroscopy （XPS） and photoluminescence （PL）. The effects of Y and Cd ions on the optical properties of the samples were studied. Doping of Y into ZnO evidently increases the intensity of UV emission, or co-doping of Y and Cd enhances the UV emission, narrows the band gap of ZnO and hence red shifts the UV emission at the same time. Therefore, Y and Cd co-doped ZnO nanopowders exhibit an intense violet emission in the room temperature PL spectrum, which could be a potential candidate material for optoelectronic applications.
基金financially supported by the National Natural Science Foundation of China(51631001,51672010 and81421004)the National Key R&D Program of China(2017YFA0206301 and 2016YFA0200102)
文摘Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a general,surfactantfree,large-scale synthesis approach for Fe3 O4 spheres.Herein,we developed a facile scalable solvothermal method in the absence of surfactants to produce Fe3 O4 spheres with the yield of 5.1 g,which present tunable sizes from 107 to 450 nm by modulated molar ratio of Fe3+/COO-in the solution.Particularly,it is observed that the reactants undergo a redox process,composed of a precipitation-dissolution equilibrium combined with a coordination reaction(termed as RPC),to the final product based on the LaMer model.It is worth noting that the generation of di-carboxyl group and its coordination with iron cations determine the formation of Fe3 O4 spheres.This work not only offers a strategy to precisely tailor the particle size in scalable synthesis process,but also gives the insight on the role of dihydric alcohol in the formation mechanism of Fe3 O4 spheres in the absence of surfactants.
