Broadband near-infrared luminescence and energy transfer of Cr3+,Ce3+ co-doped Ca2LuHf2Al3O12 phosphors

Broadband near-infrared phosphors are highly desirable for food testing.Targeted Ca2LuHf2Al3O12:Cr3+(CLHA:Cr3+) and Ca2LuHP2Al3O12:Ce3+,Cr3+(CLHA:Ce3+,Cr3+) phosphors were synthesized by the conventional high-temperature solid state reaction.The CLHA:Cr3+phosphor,with a good thermal stability,shows a red shift owing to radiation reabsorption and non-radiative transition with increasing Cr3+content.For co-doped sample,the emission intensity of Cr3+can be enhanced by three times due to the energy transfer from Ce3+to Cr3+,which can be evidenced by a significant overlap between the PLE of Cr3+single-doped phosphor and the PL of Ce3+single-doped phosphor.In addition,the mechanism of energy transfer is identified as a quadrupole-quadrupole interaction according to decay Lifetime and Dexter’s energy transfer formula.The broadband NIR emission peaked at 775 nm of CLHA:Cr3+,Ce3+phosphor shows a bright prospect in nondestructive quality-control analysis systems for food.