Achieving high quantum efficiency independent on luminescence center through sub-lattice cage engineering

Abstract Duly promoting the relating structure engineering at the level of sub-lattice can accelerate the discovery and improvement of new phosphor materials. In this paper, we describe a new concept of “sub-lattice cage engineering” as a potential design principle for designing novel Sr8MgCe(PO4)7, (Sr8-xTbx)MgCe(PO4)7 and Sr8(Mg1-yMny)Ce(PO4)7 phosphors with double cage structure. In these phosphors, the inner cage consists of three configurations: Sr/MgO8, Sr/MgO9 and PO4 polyhedrons and the outer cage is constituted by two configurations: Sr/MgO8 and Sr/MgO9 polyhedrons. Relying on this design, no matter single-emitter doping or multi-emitters doping, and no matter electron transition of homogeneous ions or energy transfer between heterogeneous ions, they all achieve a high quantum efficiency and energy transfer efficiency independent on luminescence center. As a result, the representative lanthanide ions of Ce3+ and Tb3+ as well as typical transition element of Mn2+ in these phosphors all exhibit high internal quantum efficiency (IQE) over 97.6%, 87% and 71.5% and energy transfer efficiency (ETE) of Ce3+-Tb3+ and Ce3+-Mn2+ up to 92% and 83%, respectively. All the IQE and ETE are higher than the known prominent ones for Ce3+, Mn2+ and Tb3+ doped phosphors. As the proof-of-concept, a white LED using these phosphors as the core components is fabricated, and it can be operated at high power density (>100 mA), thus further verifying their potential for some prospective applications, such as high-power lighting and laser display.