Solvothermal/hydrothermal Synthesis And Characterization Of ZnSe Microspheres And SrMoO₄: Eu³⁺ Phosphors

As one of the most vital II-VI group semiconductors, Zinc selenide （ZnSe） is nowwidely used for its unique optical properties. The application of semiconductor dependson the properties of the materials, which interrelate with geometrical factors such asmorphology, size, and crystal structure. Therefore, it is very important to develop somefacile preparation methods to control over the inorganic semiconductor crystallinestructure and shape in modern materials chemistry.Metal molybdates nanomaterials have been arousing much attention for their wideapplications in such fields as optical fibers, electro-optical device, scintillation detectors,and so forth. Among these metal molybdates, SrMoO₄with a tetragonal scheelite-typestructure is an interesting material depends on its emission of green or blueluminescence at room temperature.There are two parts in this work: one is using the surfactant and chelator-assistedsolvothermal method to synthesis ZnSe microspheres. The other is usingchelator-assisted hydrothermal method to synthesis SrMoO₄:Eu³⁺phosphors.1. We employ ethylenediamine tetraacetic acid disodium salt （Na2EDTA）,octadecylamine （ODA）, a mixed solution of de-ionized water （DIW） and ethanol（C2H5OH）, and hydrazine hydrate （N2H4·H2O） as reductant to synthesis stilleitestructure ZnSe microspheres. Experiment results indicated that reaction time, dosage ofNaOH, amount of Na2EDTA and the water/ethanol volume ratio has a strong effect onthe morphologies and sizes of ZnSe microspheres. The possible formation mechanismof ZnSe microspheres has been proposed. Finally, the structure, composition,morphology and luminescence properties of as-prepared samples are systematicallyinvestigated.2. We use Sodium citrate （Na3Cit）-assisted hydrothermal route to preparetetragonal scheelite-type structure SrMoO₄:Eu³⁺phosphors. Experiment resultsdemonstrated that the reaction temperature, amount of Na3Cit and reaction time play asignificant part in the formation of the perfect morphology and structure. The possibleformation mechanism of spindle-like SrMoO₄:Eu³⁺sample is proposed. Underultraviolet excitation （287nm）, the obtained SrMoO₄:Eu³⁺phosphors show the characteristic⁵D₀-⁷F_J（J=1,2,3,4） emission lines with red emission⁵D₀-⁷F₂（613nm） asthe most prominent group.