Near-infrared Sr7NaGa(PO4)6:Cr3+,Ln3+ (Ln = Nd, Er, and Yb) phosphors with different energy transfer paths: photoluminescence enhancement and versatility

Near-infrared phosphors are of great interest due to their unique, versatile luminescence properties and exciting application prospects. Herein, a novel broadband emission NIR phosphor Sr7NaGa(PO4)(6):Cr3+ was synthesized successfully, and photoluminescence properties of the phosphor were studied. When Ln(3+) ions were co-doped, the photoluminescence was enhanced. Compared with Sr7NaGa(PO4)(6):0.15Cr(3+), the total emission intensity of Sr7NaGa(PO4)(6):0.15Cr(3+),0.15Yb(3+) increased to 172%, the IQE of Sr7NaGa(PO4)(6):0.15Cr(3+),0.15Nd(3+) increased from 22 to 72%, and the thermal quenching of Sr7NaGa(PO4)(6):0.15Cr(3+),0.50Er(3+) suppressed effectively. Highly efficient energy transfer paths are formed in the Sr7NaGa(PO4)(6):0.15Cr(3+),Ln(3+) phosphors because of the shorter distances between Cr3+ ions and Ln(3+) ions in the Sr7NaGa(PO4)(6) host. The energy transfer efficiencies of Cr3+ -> Ln(3+) are greater than 70%. Finally, the investigations on night vision, solar cells, and ratiometric luminescent thermometers demonstrate that the as-prepared NIR phosphors have the potential for multifunctional applications.

Automated summary

Near-infrared phosphors have gained significant attention for their unique and versatile luminescence properties as well as their potential applications. In this study, a novel broadband emission NIR phosphor Sr7NaGa(PO4)(6):Cr3+ was successfully synthesized and its photoluminescence properties were investigated. Co-doping with Ln(3+) ions enhanced the photoluminescence. The as-prepared NIR phosphors showed potential for multifunctional applications such as night vision, solar cells, and ratiometric luminescent thermometers.