The extremely efficient and luminous-thermal-stable red phosphor based on new layered and rigid phosphate

Developing idea red phosphors with high quantum efficiency and excellent fluorescent thermal stability has special significance for both lighting and display devices but is still challenging. The internal quantum efficiency of Eu 3+ in reported red phosphors is generally few lower. The host takes a key role in offering special crystal local environment to Eu 3+ . In this work, inherent layered CaIn 2 (P 2 O 7 ) 2 (CIP124) phosphate with different M1 and M2 sites for Ca/In co-occupying was discovered. By introducing Eu 3+ into CIP124, high quality red light has been successfully achieved. Eu 3+ locates two positions simultaneously but prefers the symmetrically lower M2 site. The large interlayer distance reduced the possibility of effective energy capture by the quenching center thus achieved the high doping concentration of Eu 3+ . Structural refinement, vacuum-ultraviolet spectroscopy and Judd-Ofelt theory shed light on the low symmetry and stiffer environment of Eu 3+ in CIP124. CIP124: 0.2Eu 3+ shows extremely high internal quantum efficiency (99.9 %), satisfactory color purity (93.1 %), and outstanding luminous thermal stability with the emission intensity keeping 97.8 % of initial intensity at 423 K, superior to other reported red phosphors. Based on the newly developed red phosphor, an excellent white light-emitting diode (WLED) was self-fabricated. These results imply that CI 1-x P124: xEu 3+ phosphors can be used as the red component of phosphor converted WLEDs. This work proposed a new host with the layered host structure and rigid local environment which is beneficial for achieving phosphors with the superb luminous comprehensive performance. New inherent layered compound CaIn 2 (P 2 O 7 ) 2 (CIP124) with M1 and M2 sites for Ca/In co-occupying has been discovered. When Eu 3+ dissolves into CIP124, it locates two positions at the same time but prefers the symmetrically lower M2 site with rigid environment, emitting the efficient and stable red light favorable to fabricate warm white PC-LED. • Layered phosphate CaIn 2 (P 2 O 7 ) 2 (CIP124) was discovered with its structure determined. • Eu 3+ prefers to locate the symmetrically lower and rigid M2 site in CIP124. • Special environment enables the extremely intense and stable red emission of Eu 3+ . • CIP124:Eu as red component has shown a great application prospect for pc-WLED.