Highly efficient Y3-xBaxAl5-xSixO12:Cr3+ near-infrared phosphor for plant growth

Abstract

Near-infrared (NIR) phosphors enhance the growth of plants due to their superior penetration. However, relatively high thermal quenching and low quantum efficiency restrict the development of NIR phosphors. In this study, 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 bandgap 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. The optimal Ba2+-Si4+ doping concentration is 0.05 mol and the Cr3+ doping content is 0.09 mol. The critical distance (R c ) is 16.62 Å. Dipole–dipole interactions and radiation reabsorptions are main concentration quenching mechanisms. Lattice distortions occur with the introduction of Ba2+-Si4+ and the value (D r ) 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°C), 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%.