First-principles study of the electronic structure and optical properties of Eu2+ and Mn2+-doped NaLi3SiO4 phosphor

Based on the plane-wave pseudopotential method of density functional theory, it calculates and compares the electronic structure and optical properties of NaLi3SiO4 before and after doping with Eu2+ and Mn2+. It investigates the feasibility of using Eu2+ and Mn2+-doped NaLi3SiO4 phosphor in the design of resin-phosphor-resin layered films for transparent display (TD) screens. The electronic structure analysis indicates that NaLi3SiO4 is an indirect bandgap compound with a bandgap value of 4.56 eV, capable of sustaining the energy difference between the ground state and the excited state of activator ions. Doping with Eu2+ and Mn2+ increases the crystal volume, reduces the bandgap, and results in a more compact band structure, making it easier for electrons to transition from the valence band to the conduction band. According to the optical properties analysis, NaLi3SiO4 is an excellent transparent material in visible and infrared light regions. Doping with Eu2+ and Mn2+ enhances the light absorption capacity of NaLi3SiO4 in the 0–5 eV energy range. Combined with its refractive index and reflectivity, it is evident that NaLi3SiO4: Eu2+ and NaLi3SiO4: Mn2+ phosphors exhibit good transparency in the visible light region. Therefore, they can become critical materials for designing resin–phosphor–resin layered films for TD screens. Graphical abstract