Structure–Optical Behavior Correlation, Optimized Photoluminescence, and DFT Calculation of La₇O₆(BO₃)(PO₄)₂:Sm³⁺ Micropowder for Solid State Lighting

To promote the development of the solid state lighting and display industry, exploring excellent inorganic phosphors has always been a hot scientific and applied issue. Herein, we have constructed a series of Sm3+-activated La7O6(BO3)(PO4)2 (abbreviated as LBPO) phosphors by means of the short-time high-temperature solid phase synthesis process. The crystalline phase composition, micromorphology feature, ionic states of elements, and diffuse reflectance absorption performance were solved in detail. LBPO is suitable as phosphor host materials according to the investigation on electronic properties by density functional theory. The excitation and emission performance is significantly influenced by the crystalline structure of the LBPO host and doped Sm3+ concentration. The optimized photoluminescence strategy is presented: upon the strongest near-ultraviolet (UV) excitation of 404 nm, LBPO:7% Sm3+ displays intense orange-red visible luminescence with the dominant emission at 605 nm (4G5/2 → 6H7/2 of trivalent samarium). Its concentration quenching mechanism is the dipolar interaction. On the basis of the investigation of the detailed CIE chromaticity coordinate, color purity (CP), correlated color temperature (CCT), and internal quantum efficiency (IQE), we may use LBPO:Sm3+ micropowder as an alternative ingredient for phosphor-converted near-UV-based warm white LEDs.