A Highly Efficient Y3-Xbaxal5-Xsixo12:Cr3+ Near Infrared Phosphor for Plant Lighting

Near-infrared (NIR) phosphors enhance the growth of plants due to its superior penetration. However, a relatively high thermal quenching and low quantum efficiency restrict the development of NIR phosphors. In this work, Y3-xBaxAl5-xSixO12:Cr3+ phosphors (YBAS:Cr3+) with varying concentrations of Ba2+-Si4+ and Cr3+ were studied. The results demonstrate high purity phases are obtained with doping Ba2+-Si4+ and Cr3+. The Ba2+-Si4+ doping enhances crystallinity and near-spherical particles are synthesized. The theoretical calculations indicate a significant reduction in band gap with doping Ba2+-Si4+, resulting in impurity levels appearing in the valence band region. The state density calculation shows that the band formation is contributed by all elements. Optimal Ba2+-Si4+ doping concentration is 0.05 mol and Cr3+ doping content is 0.09 mol. The critical distance (Rc) is 16.62 Å. Dipole-dipole interactions and radiation reabsorptions are main concentration quenching mechanisms. Lattice distortions occur with introducing Ba2+-Si4+ and the value (Dr) is 0.052. The YBAS:0.09Cr3+ phosphor shows a crystal field strength with a Dq/B value of 2.76. The phosphor exhibits a high quantum efficiency (73.42%), superior thermal quenching resistance (~70% initial intensity at 150℃), and a suitable fluorescence lifetime (130.04 μs). A near-infrared pc-LED with YBAS:0.09Cr3+ phosphor displays a high output power of 167.12 mW and a moderate conversion efficiency of 3.82%.