Preparation and Characterization of Fe-Containing Aluminosilicate Phosphate Ceramic-Glass from a Geopolymer Precursor: Insights from XRD, Raman Spectroscopy, and Optical Properties

In this study, Fe-Al₂O₃-SiO₂-P₂O₅ (FASP) glass–ceramic was prepared by heating Fe-acid-based geopolymer at 1050 °C. The Fe-geopolymer was obtained by mixing metakaolin and Fe filings with diluted phosphoric acid solution. X-Ray Diffraction (XRD) and Raman spectroscopies measurements were used to found the phase composition of the material. According to the results of XRD, the glass–ceramic contains AlSi₂P₃O₁₂ and AlPO₄ nanocrystals and an amorphous phase. With Raman spectroscopy we recognized the presence of AlPO₄ and FeO_x entities. Si–O-P, P-O-P bonds, and O = P double bonds are also identified. Glass–ceramic has been investigated for its semiconductor and linear and nonlinear optical properties. The variations of optical properties were further evaluated by UV–Visible and fluorescence spectroscopies. The chromaticity coordinates, and the fluorescence decay lifetime are recorded, analyzed and discussed. The nonlinear optical parameters are also determined and discussed. The FASP glass–ceramic exhibited an excellent UV–Visible absorption, a wide direct bandgap (3.72 eV), a distinguished fluorescence emission, a significant value of fluorescence decay lifetime 106 ns is showed. Thus, FASP glass–ceramic could have potential applications in solar cell and nonlinear optical devices.