Broadband near-infrared luminescence in garnet Y3Ga3ZnAO12 (A = Ge, Si):Cr3+ phosphors

In this work, novel Cr³⁺-doped near-infrared phosphors Y₃Ga_(3-x)ZnAO₁₂ (A = Ge, Si):xCr³⁺ were synthesized by the solid-phase reaction method. Their crystal structures and luminescence properties were studied. The excitation spectra of Y₃Ga_(3-x)ZnAO₁₂ (A = Ge, Si):xCr³⁺ at 453 nm and 632 nm correspond to the Cr³⁺ spin-allowed d-d transitions ⁴A_2g-⁴T_1g (4 F) and ⁴A_2g-⁴T_2g (4 F), respectively. The near-infrared emission peak observed at 783 nm (FWHM ≈ 130 nm) is induced by the ⁴T_2g-⁴A_2g transitions of Cr³⁺. Additionally, the luminescence performance of Y₃Ga_(3-x)ZnAO₁₂ (A = Ge, Si):xCr³⁺ phosphors were successfully enhanced by Si⁴⁺-Ge⁴⁺ ions substitution. The emitting intensities of Y₃Ga₃ZnGeO₁₂:0.05Cr³⁺ and Y₃Ga₃ZnGe_0.8Si_0.2O₁₂:0.05Cr³⁺ remain 56 % and 49 % at 423 K of their initial value at 298 K, respectively. The above results indicate that the excitation wavelengths of Y₃Ga_(3-x)ZnAO₁₂ (A = Ge, Si):xCr³⁺ phosphors match well with commercial 460 nm blue light chips, suggesting their potential applications in medical imaging, night vision and non-destructive testing.