Cr3+掺杂Ca4HfGe3O12宽带近红外荧光粉的发光特性及应用

近红外荧光粉在生物活体成像领域展现出重要的应用前景。但活体成像用近红外荧光粉存在种类匮乏、耐温性差等瓶颈问题。采用固相法合成了宽带近红外Ca₄HfGe₃O₁₂∶ xCr³⁺(0≤x≤0.09)荧光粉。X射线衍射和能谱分析的结果表明Cr³⁺离子成功进入Ca₄HfGe₃O₁₂晶格。在469 nm蓝光激发下，Ca₄HfGe₃O₁₂∶xCr³⁺荧光粉发射出690~1 200 nm的宽带近红外光，峰值波长为825 nm (⁴T₂-⁴A₂)，半高宽达到141 nm，Cr³⁺掺杂最佳浓度为0.03。依据激发光谱峰形和寿命衰减行为，证实Cr³⁺仅占据基质中一种阳离子格位。Ca₄HfGe₃O₁₂∶0.03Cr³⁺荧光粉的荧光量子效率为33.63%，该荧光粉发射光谱在400 K下的积分面积为室温下的60.5%，表明该样品具有优良的热稳定性。采用自制近红外荧光粉转换器件照射人手掌和滤波片遮挡的水果，观察到清晰地静脉血管和遮挡水果的轮廓。

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 imaging. However, the near-infrared phosphor for organism imaging has some bottleneck problems such as a lack of variety 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 fluorescence 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 illuminate the palm of the human hand and the fruit shielded by the 700 nm filter, and the venous vessels and the shelterfruit outline were clearly observed.