Luminescence characteristics and device applications of Cr3+-doped Ca4HfGe3O12 broadband near-infrared phosphors
Near-infrared phosphor has shown an important application prospect in the fields of living organism imag-ing.However,the near-infrared phosphor for organism imaging has some bottleneck problems such as a lack of vari-ety and poor thermal stability.Broadband near-infrared Ca4HfGe3O12∶xCr3+(0≤x≤0.09)phosphors were synthesized by the solid phase method.X-ray diffraction and energy spectrum analysis showed that Cr3+ions successfully entered the Ca4HfGe3O12 crystal lattice.Upon 469 nm excitation,Ca4HfGe3O12∶xCr3+phosphors presented a width emission band covering 690-1 200 nm(strongest peak of 825 nm for 4T2-4A2,bandwidth of 141 nm)with a fluores-cence quantum efficiency of 33.63％(x=0.03),which exhibited good thermal stability,60.5％of room temperature intensity at 400 K.The excitation peak shape and lifetime decay behavior results showed that Cr3+occupies only one cation sites in the matrix.In addition,the self-made near-infrared phosphor conversion device was used to illumi-nate the palm of the human hand and the fruit shielded by the 700 nm filter,and the venous vessels and the shelter-fruit outline were clearly observed.
thermal stabilityCa4HfGe3O12near-infrared phosphorCr3+ionsoptical material
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