A New Efficient Deep-Red-Emission Phosphor Y3Al4.9Sb0.1O12: Ce3+, Cr3+ with Application Potential in Plant Growth

Abstract

Aiming at a system of more efficient plant growth, cationic substitutions for garnet-structure host crystal activated by Ce3+ and Cr3+ are investigated. A series of Y3Al5O12: Ce3+-Cr3+, red-emitting materials excited by near-ultraviolet and blue light with a peak emission near 693 nm, are synthesized using a solid-state method. The substitution of Sb3+ for Y3Al5O12: Ce3+, Cr3+ is found to increase the emission intensity of deep red about +80% because it improves the energy transfer from Ce3+ to Cr3+, where yellow emission of Ce3+ is depressed and deep red of Cr3+ increased. It also enhances the intensity-ratio of zero phonon line (ZPL) vs phonon assisted side band. It is induced that the substitution of Sb3+ having strong covalent property influences symmetric Ce3+O2– 6 octahedron, significantly increasing the intensity of 2E→4A2 ZPL of Cr3+ under the resonance energy transfer of Ce3+ to Cr3+. From the ratio of Ce3+ emission intensity in the absence and presence of Cr3+, the energy transfer has a mechanism of dipole-quadrupole interaction. By using Sb3+ substitution and flux AlF3, the original emission intensity of Y3Al5O12: Ce3+, Cr3+ is increased about +183%. The new phosphor has application potential for plant growth in both methods of using LED and converting Sunlight.