A novel deep-blue emitting BaSr2(PO4)2: Eu2+ phosphor with excellent thermostability for advanced anti-counterfeiting and white light-emitting diodes

A novel class of Eu 2+ -activated BaSr 2 (PO 4 ) 2 phosphors with efficient deep-blue luminescence was successfully synthesized via a high-temperature solid-state reaction. The rigid phosphate framework provides a distinctive coordination environment for Eu 2+ , leading to enhanced luminescent thermal stability. Structural and morphological characterization confirmed the phase-pure formation, with Eu 2+ ions effectively incorporated into the host lattice. The optimal sample (BaSr 2 (PO 4 ) 2 : 0.03Eu 2+ ) exhibits an intense deep-blue emission centered at 416 nm under 348 nm near-ultraviolet irradiation and concentration quenching occurs beyond the optimal doping level due to dipole-dipole interactions. The phosphor demonstrates outstanding thermal stability, retaining 92.23 % of its room-temperature intensity at 423 K, and possesses an internal quantum efficiency (IQE) of 41.19 %. Fabricated white light-emitting diodes, employing this phosphor, produce warm white light with high color rendering (CRI = 93.1) and a correlated color temperature of 4652 K. Additionally, the phosphor was effectively utilized in anti-counterfeiting inks. This study demonstrates that BaSr 2 (PO 4 ) 2 : Eu 2+ phosphors not only possess excellent thermal stability but also show great potential for both anti-counterfeiting security inks and white light-emitting diodes applications, providing a valuable strategy for developing efficient deep-blue phosphors.