Growth characteristics of copper nanowires and new chemical routes for the synthesis of K2SiF6:Mn4+ phosphors
| Autor: | Tung-Jung Lin, 林彤蓉 |
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| Rok vydání: | 2018 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 106 In the first part, one-dimensional copper nanowires (CuNWs) are synthesized via galvanic displacement reaction and the growth characteristics of CuNWs are studied by TEM and EDS mapping. As the reduction-oxidation reaction occurs on the solid-liquid interface, the Cu2+ ions on the Al foil surface are reduced to Cu nanoparticles which aggregate on the substrate surface during the initial reaction. The aluminum oxidizes into Al3+ ions and subsequently forms the AlOxHy interlayer between Al foil and Cu nanoparticles. By adding surfactant of CTAC, CuNWs grow on the Cu nanoparticle seeds in the [100] direction when the reaction time increases. In the second part, K2SiF6:Mn4+ powders are synthesized by co-precipitation reaction via a new chemical route. The structural, morphological and optical properties of the K2SiF6:Mn4+ powder are characterized by using powder X-ray diffraction, scanning electron microscope and photoluminescence spectroscopy, respectively. The compound is prepared by adding potassium silicate, KF and KMnO4 in an HF acidic solution following the reduction of Mn7+ to Mn4+ by using H2O2 at room temperature. By using PEG as surfactant, particles sized of K2SiF6:Mn4+ powders is about 5-10 μm. Moreover, Na2SiF6:Mn4+ powders are also successfully synthesized using this new chemical route. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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