Structure and luminescence of core-shell phosphor aluminate-boron oxide
| Autor: | Chen-Yu Wu, Chien-Ming Lei, Toshiaki Takei, Horng-Yi Chang, Chau-Chang Chou, Shing-Hoa Wang, Rudder T. Wu |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Photoluminescence Annealing (metallurgy) Mechanical Engineering Aluminate Metals and Alloys Analytical chemistry Infrared spectroscopy Sintering Phosphor 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences 0104 chemical sciences chemistry.chemical_compound chemistry Mechanics of Materials Boron oxide Materials Chemistry 0210 nano-technology Luminescence |
| Zdroj: | Journal of Alloys and Compounds. 743:506-513 |
| ISSN: | 0925-8388 |
| Popis: | Long-afterglow phosphor SrAl2O4: 0.01Eu2+, 0.01Dy3+ (SAO) requires a high sintering temperature of 1400 °C even when boric acid is added as flux via a solid-state reaction. The aluminum source NaAlO2 behaved as a good mineralizer in the designed hydrothermal process to achieve a large surface-to-thickness ratio of SAO. The flower-like shape of hydrothermally prepared hSAO without B2O3 after annealing at 1100 °C/4 h transformed into a rod-like plate phosphor with nano-thickness. Such a small rod-like plate exhibited higher photoluminescence (PL) intensity than large-grained B2O3-added bSAO prepared via a solid-state reaction. The annealed hSAOs inherited the morphology of the as-hydrothermally prepared aluminates. A nano-thick sheet of annealed aSAO containing B2O3 further enhanced the PL significantly and indicated a blue shift independent of the grain size. Furthermore, the nano-thick sheet of phosphors exhibited the same afterglow as the conventional tens-of-micrometers-sized phosphors. Fourier-transform infrared spectroscopy and X-ray diffraction results showed that the B O4 bond may substitute Al O4 in the structure and the B O3 bond is in a flux outside the annealed aSAO and bSAO grains. The molten flux formed a thin layer on the surface of the SAO particles to be a core-shell of the SAO-B2O3 structure, behaving as a diffusion-assistant medium and environmental protection layer against acid and humidity. |
| Databáze: | OpenAIRE |
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