High quenching concentration of the CaLuAlO4:Er3+ upconversion phosphor with short-range energy migration.

Low activator concentration in upconversion phosphors has been a hindrance in improving luminescence performance. Herein, we report an Er³⁺ doping concentration as high as 30 at. % in the CaLuAlO₄ upconversion host. The CaLuAlO₄:Er³⁺ phosphors were prepared by the traditional high-temperature solid-state method. Under the excitation of a 980 nm laser, the optimal concentration of Er³⁺ approaches 30% according to the total integrated intensity of red and green upconversion luminescence. This quenching concentration is one order of magnitude higher than that in the traditional Er³⁺ doped upconversion polycrystals. The results obtained from first-principles calculations suggest that there are no in-plane or chain rare-earth ions in the cell. This increases the difficulty of propagating excitation energy to quench centers and is advantageous for high doping concentration. Our work can spark people's interest in the research and application of highly doped upconversion phosphors. [ABSTRACT FROM AUTHOR]