Tetracoordinate Fe3+ Activated Li2ZnAO4 (A = Si, Ge) Near-Infrared Luminescent Phosphors

摘要

Fe3+-doped near-infrared (NIR) phosphors havereceiveda lot of interest because they are nontoxic, inexpensive, and ecologicallybenign. In this work, Fe3+-activated Li(2)ZnAO(4) (A = Si, Ge) phosphors were synthesized by solid-phase reactions,in which Fe3+ entered the Zn2+ tetrahedral site.When excited by 300 nm UV light, broad NIR emission bands at 750 nm(Li2ZnSiO4: Fe3+) and 777 nm (Li2ZnGeO4: Fe3+) were observed, with internalquantum efficiencies (IQE) of 62.70% (Li2ZnSiO4: Fe3+) and 30.57% (Li2ZnGeO4: Fe3+). The thermal stability was increased from 35.43 to 49.79%at 373 K via cationic regulation. The combination of activation energy,electron-phonon coupling, and Debye temperature explained theimproved thermal stability of Li2ZnGeO4: Fe3+ phosphor. Besides, the as-synthesized phosphor demonstratedsensitive and selective Cu2+ ion detection. @@@ The differences in the thermal stabilityof the Fe3+-doped Li(2)ZnAO(4) (A = Si,Ge) phosphors wereexplained by the activation energy, Huang-Rhys factor, andDebye temperature. The quantum yield of Li2ZnSiO4:0.4%Fe3+ phosphor reached 62.70%. Besides, the as-synthesizedphosphor demonstrated sensitive and selective Cu2+ iondetection.

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