A novel broadband BaCa(BO)(SiO)Cl:Mn near-infrared phosphor with a special pseudo-octahedral Mn coordination structure.

A pseudo-octahedral coordination structure of Mn has been innovatively designed, which has realized the maximum red shift and the widest full width at half-maximum (FWHM) of Mn emission so far, not only extending the emission wavelength of Mn to the near-infrared (NIR) region, but also effectively broadening its bandwidth. In the BaCa(BO)(SiO)Cl:Mn (BCBSC:Mn) phosphor, the [Mn/Ca1O] polyhedron contains one [Mn/Ca1O] octahedron, which constitutes the pseudo-octahedral coordination structure of Mn. The BCBSC:Mn phosphor can be excited at 362 nm and 470 nm and exhibits a broadband NIR emission centered at ∼756 nm with a super-wide range from 650 nm to 1100 nm. The FWHM can reach ∼90 nm. In addition, the internal quantum efficiency (IQE) of the BCBSC:0.01Mn phosphor is 69.7%. The unique luminescence characteristics of BCBSC:Mn phosphors are explored using experimental data and first principles calculation. The significant redshift, the abnormal broadband emission, and the high luminous efficiency are closely related to the special highly distorted [Mn/Ca1O] pseudo-octahedral coordination environment. The results contribute to comprehending the mechanism of the broadband NIR emission of Mn activated phosphors and broaden the research ideas of developing high-performance Mn doped phosphors for NIR phosphor-converted light-emission diode applications.