Tunable white light of multi-cation-site Na2BaCa(PO4)2:Eu,Mn phosphor: synthesis, structure and PL/CL properties

Abstract

Novel single-phase phosphors with the multi-cation-site Na₂BaCa(PO₄)₂:Eu,xMn were synthesized by a traditional solid-state reaction method. The photoluminescence (PL) investigation indicated that the emitting light was tunable from blue to yellow with a variation in the Mn content and reaches a warm white with the CIE coordinate of (0.36, 0.32) and corresponding color temperature (CCT) of 4346 K when x is 0.07. The framework of the NBCP was compact, and the Ca²⁺ polyhedron is coplanar with the Ba²⁺ polyhedron one by one along the c axis, sharing 6 O²⁻ ions on the edge. This is the reason for the excellent thermally stability of the phosphors, which keep more than 90% of the initial PL intensity under 150 °C. Based on these facts, NBCP:Eu,xMn has potential application as a white light emitting diode (WLED). Cathodoluminescence (CL) properties were also investigated, and the phosphor has considerable luminescence intensity and high current saturation intensity.