Energy transfer enhanced broadband near-infrared phosphors: Cr3+/Ni2+ activated ZnGa2O4-Zn2SnO4 solid solutions for the second NIR window imaging dagger

摘要

Near-infrared luminescent materials have attracted considerable interest because of their excellent performance in the field of optical imaging. Here, a series of Cr3+/Ni2+ co-doped near-infrared phosphors Zn1+ySnyGa2-2yO4 (ZSGO) were synthesized via a solid-state reaction. The phosphors show broad emissions in the range of 1100-1700 nm in the second NIR window. The emission intensity of Ni2+ could be greatly enhanced owing to the energy transfer from Cr3+ to Ni2+. The energy transfer mechanism was inferred from the excitation and emission spectra and the decay lifetime curve, which confirm that the primary process is the electric dipole-dipole interaction. In order to evaluate the potential optical imaging application, NIR-LED light source packages were fabricated with Cr3+/Ni2+ co-doped Zn1+ySnyGa2-2yO4 (ZSGO) phosphors and blue LED chips, which revealed high stability and a strong transilluminated biological tissue effect. These results indicate a great prospect in advanced optical imaging for NIR pc-LED applications.