Insight into crystal structure and Eu/Tb doped luminescence property of a new phosphate

Highlights: • A new compound Mg₃In₄P₆O₂₄ (MIP) was confirmed with the crystal structure solved. • Eu³⁺/Tb³⁺ single-doped and co-doped MIP phosphors were synthesized. • Photoluminescence properties of the phosphors under VUV-UV excitation were investigated. • Temperature-dependence properties of the phosphor were studied. • Emission color can be adjusted by changing Eu³⁺/Tb³⁺ concentration or by altering the excitation wavelength for a very phosphor. Luminescent materials were of vital importance in the display, lighting, and biomedical fields. Exploration of novel inorganic host materials and groping for novel color-tunable phosphor materials with good thermal stability is still a major challenge for the quality-improvement of FLs and LEDs. In the present work, a new magnesium indium phosphate, Mg₃In₄P₆O₂₄ (MIP), was successfully synthesized by conventional high-temperature solid-state reaction and was structurally characterized by powder X-ray diffraction analysis, in which magnesium and indium atoms co-occupy four metal cation sites, coordinating with adjacent oxygen atoms forming distorted MO₅ and MO₆ polyhedra. The VUV-UV excited luminescence properties of a series of Eu³⁺/Tb³⁺ doped MIP phosphors were investigated, with the temperature-dependence of photoluminescence and relative mechanism analyzed. Under the excitation of 254 nm, the MIP: Eu_xTb_y phosphors can generate bright color-tunable green-yellow-red light by changing the doping concentration. In addition, the color of emission can also be adjusted by altering the excitation wavelength for a very phosphor, MIP: Eu_0.01Tb_0.05. As an interesting discovery, the plot of integrated dominant emission intensities of Eu and Tb in phosphor MIP: Eu_0.01Tb_0.05 versus excitation wavelength exhibits analogical profile with the excitation spectra of Eu³⁺/Tb³⁺ single-doped MIP phosphor. Moreover, the representative phosphor MIP: Eu_0.01Tb_0.05 shows favorable thermal stability. Present work indicates that Mg₃In₄P₆O₂₄ is a promising host material for the fabrication of new phosphors.