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Preparation and Properties of Manganese-doped Zinc Oxide and Zinc Sulfide Transfer Agents and Light Conversion Films

Author: SongMeiQin
Tutor: SuGe
School: Ocean University of China
Course: Materials Science
Keywords: ZnO:Mn ZnS:Mn light conversion agents (films) PE PMMA
CLC: TB383
Type: Master's thesis
Year: 2012
Downloads: 147
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Abstract


Light conversion films are generally divided into two kinds of red lightintensifying membrane and blue light intensifying membrane. The red membrane isable to increase the effective light and improve the greenhouse temperature; the bluemembrane not only can increase the effective luminous flux and improve thegreenhouse temperature, but also be able to inhibit the reproduction of the pathogen,therefore, these two films will have broad application space in agriculture. There arethree main ways to prepare the light conversion films, they are attached dye method,the master batch method and the three-tier co-extrusion method.Up to now, the common conversion films are the rare earth composite conversionfilms, having been applied to actual production. However, because the rare earthelements are expensive and the equipment is complicated, their widespreadapplication has been limited. It becomes necessary to investigate inorganic lightconversion agents with low cost, which will certainly promote the development ofagricultural science and technology.First, their morphology, component and light conversion properties of theobtained two kinds of powders were investigated. Sol-gel and solvothermal methodswere chose to prepare ZnO:Mn and ZnS:Mn luminescence powders with different Mndosages, respectively. Then, the surfaces of the powders were modified. Finally, theZnO:Mn powders were mixed into polyethylene (PE) and the ZnS:Mn powders intopoly (methyl methacrylate)(PMMA), respectively.Results show that (1) The hexagonal wurtzite structure of ZnO:Mnnanoparticles was prepared with relative uniform size distribution and smooth surface.With the increase of the initial concentration of manganese, the particle size of ZnO:Mn was found to be reduced, becoming strip shape. Fluorescence properties ofthe luminescence agent were tested. The emission peak of pure zinc oxide at500~600nm was found. When the manganese ions were doped into the zinc oxide, there aretwo peaks occurred at about500nm and620nm, respectively. When the initialmanganese concentration was of3%, the luminescent properties of ZnO:Mn was thebest.(2) The ZnS:Mn particles prepared are cubic sphalerite polycrystalline structure.They are in the regular spherical shape with uniform size distribution. With theincrease of the initial concentration of manganese, they were also refined. For thefluorescence spectrum of the ZnS:Mn particles, it was found that the incorporation ofmanganese ions had an impact on the light-emitting position of the zinc sulfide,giving rise to a redshift.(3) Polyethylene film mixed with the modified ZnO:Mnpowders was tested by an ultraviolet analyzer, result shows that the transmittance ofthe low density polyethylene film has not been impacted by ZnO:Mn.(4) The PMMAfilm and the composite film of PMMA mixed with the modified ZnS:Mn powderswere tested by a fluorescence analyzer, it is found that the pure PMMA film did notemit. While, when the ZnS:Mn powders were mixed into the PMMA film, theemission peak appeared, and with the increase of the initial concentration ofmanganese, the luminescence peak at560~590nm red-shifted gradually.

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