Structural transformations and optical properties of glass-ceramics based on ZnO, β- and α-Zn2SiO4 nanocrystals and doped with Er2O3 and Yb2O3: Part I. The role of heat-treatment
| Autor: | Pavel Loiko, M. Tsenter, Elena Vilejshikova, Alexander A. Zhilin, Alexander Khubetsov, P. A. Petrov, Olga Dymshits, Alexander V. Baranov, Irina Alekseeva, Anastasia Bachina, Anna Volokitina, D. V. Shemchuk |
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| Rok vydání: | 2018 |
| Předmět: |
Materials science
Doping Biophysics 02 engineering and technology General Chemistry 010402 general chemistry 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Biochemistry Atomic and Molecular Physics and Optics 0104 chemical sciences law.invention symbols.namesake Differential scanning calorimetry Nanocrystal Chemical engineering law Transmission electron microscopy symbols Absorption (chemistry) Crystallization 0210 nano-technology Luminescence Raman spectroscopy |
| Zdroj: | Journal of Luminescence. 202:47-56 |
| ISSN: | 0022-2313 |
| Popis: | Differential scanning calorimetry, X-ray diffraction analysis, transmission electron microscopy, high- and low-frequency Raman and optical spectroscopy were applied to the study of structural transformations in glass of the K2O – ZnO – Al2O3 – SiO2 system codoped with Er2O3 and Yb2O3 and subjected to heat-treatments at 680–1300 °C. Transparent glass-ceramics based on ZnO nanocrystals are prepared by heat-treatments at 680–800 °C, while at 860–900 °C, β-Zn2SiO4 (β-willemite) nanocrystals precipitate in addition to ZnO; α-Zn2SiO4 nanocrystals appear additionally at 950 °C, and the material loses transparency. Opaque glass-ceramic prepared by heat-treatments at 1000 °C contains only crystals of ZnO and α-Zn2SiO4, while crystallization of potassium aluminosilicates, KAlSi2O6 (from the surface) and KAlSiO4 (from the bulk) in addition to ZnO and α-Zn2SiO4, is observed at above 1000 °C. Optical absorption and luminescence of the initial glass and GCs are reported. A shift of the UV absorption edge and the near-IR losses due to the free charge carrier scattering are indications of the ZnO crystallization. Multiple visible emissions from the glass and GCs are determined by the Er3+ ions, nanocrystals of α-Zn2SiO4 and defects of the ZnO nanocrystals. The color of the latter emission can be tuned by varying the heat-treatment temperature. The rare-earth ions (RE3+) do not enter into the Zn-containing nanocrystals and remain in the residual glassy phase until ~ 1200 °C, when the RE silicates (RE2Si2O7) are formed resulting in structured intense Er3+ emission. |
| Databáze: | OpenAIRE |
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