Investigating Raman spectra and density functional theory calculations on SrAl2O4 polymorphs

Abstract

SrAl2O4 is a long-lasting material that combines several favorable attributes in comparison with their inorganic luminescent predecessor. In addition, it is an intriguing material combining a structural polymorphism with potential application such as in solar cells, biological labeling and imaging, and security encode. Here, we unambiguously determinate the Raman spectra for hexagonal and monoclinic polymorphs. Specifically, the Raman mode assignment of phonon modes obtained experimentally is done for the first time by modeling these structures following the principle calculations within the framework of the density functional theory. Several functionals are evaluated, considering the agreement of the calculated modes with the experimental data. The optimized structure is obtained, first, on the basis of minimizing the total energy of the structure. The calculated vibrational modes show qualitative agreement with the experimental observation. This study offers a new insight to study the relationships between structural and optical behavior in this system, providing tools to design new technological applications.