A New Efficient Deep-Red-Emission Phosphor Y₃Al_4.9Sb_0.1O₁₂: 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 693nm, 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.

Crystal-field regulation enables broadband-to-line emission switching in Cr3+-activated pyroxenes

“…As a unique luminescence activator, transition metal (TM) ions Cr 3+ -doped deep-red and near-infrared (NIR) phosphors have received much attention in recent years due to their high performance. 1–4 In general, Cr 3+ ions strongly prefer to occupy the octahedral sites in the crystal lattice. 5 The photoluminescence (PL) properties of Cr 3+ -activated materials are determined by the energy of the excited state levels 2 E and 4 T 2 and the ground state level 4 A 2 , which are strongly dependent on the crystal field strength of the host lattice.…”