La3Ga5SiO14:Cr3+: A broadband near-infrared phosphor induced by the two-site occupation of Cr3+

The broadband near-infrared phosphors are feasible to apply in real-time nondestructive examination . In this work, La 3 Ga 5 SiO 14 :Cr 3+ phosphors with the broadband near-infrared emission have been synthesized using a solid state reaction method. Their optical characteristics were investigated via the measurements of ultraviolet–visible diffused reflectance and luminescence spectra. The occupations of Cr 3+ ions in La 3 Ga 5 SiO 14 host were inquired by the X-ray absorption near edge structure and electron paramagnetic resonance analyses. The results indicate that Cr 3+ ions substitute octahedral and tetrahedral Ga 3+ ions in La 3 Ga 5 SiO 14 host, which results in a sharp emission band coming from the 2 E g → 4 A 2g transitions of Cr 3+ and a wide emission band coming from the 4 T 2g → 4 A 2g transitions of Cr 3+ . The fabricated NIR pc-LED device by combining the synthesized La 3 Ga 5 SiO 14 :0.10Cr 3+ phosphor with a blue LED chip indicates that the La 3 Ga 5 SiO 14 :Cr 3+ phosphors have potential applications in nondestructive examination.