Result and Discussion
The XRD results show that well crystalline willemite (Zn2SiO4) with the contribution of dopant (Er3+) in the lattice can be achieved at the temperature of 900 °C. The XRD results also show that rhombohedral crystalline willemite was formed by mixing ZnO and SLS glass and optimum heat treatment of 1000 °C to produce willemite-based glass-ceramics, the solid-state reaction between well-crystallized willemite and Er3+ was obtained at 900 °C sintering temperature, and Er3+ can be completely dissolved in the lattice at this temperature. FTIR results confirmed the appearance of the vibrations of SiO4 and ZnO4 groups which clearly suggests the formation of the Zn2SiO4 phase; the compositional evaluation of the FTIR properties of the [(ZnO)0.5(SLS)0.5]1−x[Er2O3]x system indicates that the presence of erbium ions affects the surrounding of the Si–O and trivalent erbium occupies their position; these agree with the XRD data at the peak positioned at 20.29°. The most significant modification produced by the addition of erbium and the increase of the heat treatment temperature of the studied samples shows a drop in the intensity of FTIR band located at 513 cm−1, which indicates that the addition of erbium oxide and increase in the sintering temperature decline the presence of SiO4 group. The microstructure analysis of the samples using FESEM shows that the average grain size of samples tends to increase from 325.29 to 625.2 nm as the sintering temperature increases. Finally, the UV-VIS spectra of all doped glass-ceramics depict absorption band due to host matrix network and the presence of Er2O3. The results show that the intensity of the bands tends to grow by increasing the Er2O3 content in the range of 1–5 wt.% and the sintering temperature in the 500–900 °C range, followed by a drop at the temperatures of 1000 and 1100 °C. By adding the Er2O3 content to the host network and increasing the sintering temperature from 500 to 900 °C , the intensity of UV-VIS bands situated between 400 and 1800 nm increased due to the absorption of Er3+ions and the host crystal structure. The intensity of the UV bands was observed to have dropped when the sintering temperature was increased to 1000 and 1100 °C, which indicates that by going to the temperature of 1000 and 1100 °C, the Er2O3 particles tend to produce cluster that causes the decrease in the UV absorption bands. For the sample with x = 5 wt.% Er2O3, two strong absorption bands situated at about 1535 and 523 nm were observed. These bands were attributed to the optical transition from 4I15/2 to 4I13/2 and 4S3/2 state, respectively.
KeywordsWillemite (Zn2SiO4) Rhombohedra crystalline willemite Erbium oxide UV-VIS bands
- 8.W. Kaewwiset et al., ESR and spectral studies of Er3+ ions in soda-lime silicate glass. Phys. B. 409, 24–29 (2013)Google Scholar
- 10.S. Kanagesan, S. Jesurani, R. Velmurugan, C. Kumar, T. Kalaivani, Magnetic hysteresis property of barium hexaferrite using D-fructose as a fuel. J. Mater. Sci. Eng. 4, 88–92 (2010)Google Scholar
- 12.Q. Chen, M. Ferraris, D. Milanese, Y. Menke, E. Monchiero, G. Perrone, Novel Er-doped PbO and B2O3 based glasses: investigation of quantum efficiency and non-radiative transition probability for 1.5 μm broadband emission fluorescence. J. Non-Cryst. Solids 324(1–2), 12–20 (2003)CrossRefGoogle Scholar
- 25.F.F. Bentley, L.D. Smithson, A. L. Rozek, Infrared Spectra and Characteristic Frequencies 700–300 cm −1, vol. 68, no. 1 (Interscience Pub., New York, 1968), pp. 103–188.Google Scholar
- 27.B.N. Figgis, Introduction to Ligand Field Theory (Wiley, New York, 1966)Google Scholar