An efficient red phosphor LuNb2VO9:Eu3+ with broadband excitation and abnormal thermal quenching properties for personal identification, security ink, and w-LEDs

A series of red-emitting phosphors LuNb ₂VO ₉ (LNV): xEu ³⁺ ( x = 0.5–45 mol%) were successfully obtained through the high-temperature solid-state reaction. The structure, phase purity, photoluminescence spectra, thermal stability properties, and color purity of the obtained phosphors were systematically examined. The LNV:Eu ³⁺ phosphor exhibits broadband excitation due to the O ^2-→Eu ³⁺ and O ^2-→V ⁵⁺ charge transfer. The LNV:Eu ³⁺ phosphor excited at 316 nm shows four emission peaks at 595, 615, 619, and 699 nm, corresponding to electron transitions from the ⁵D ₀ level to the ⁷F ₁, ⁷F ₂, ⁷F ₃ and ⁷F ₄ levels. The optimal doped concentration of LNV: xEu ³⁺ is x = 10 mol%. The quenching mechanism is attributed to the nearest neighbor ion interaction. Furthermore, the prepared phosphor exhibits good thermal stability and remarkable activation energy E _a (0.74 eV). In addition, LNV:Eu ³⁺@oleic acid (OA) readily exhibits the level I-III characteristics of fingerprints and the detailed characteristics of lip lines. The successful utilization of LNV:Eu ³⁺ in anti-counterfeiting ink has yielded impressive results. The Commission International de L′ Eclairage (CIE) coordinate of the prepared white light-emitting diode (w-LED) in this study is (0.331, 0.367), accompanied by a color rendering index ( R _a) of up to 95. Notably, the results of these experiments indicate that LNV:Eu ³⁺ phosphor possesses exceptional luminescence properties and holds promising applications.