Study on the red/far-red emitting Mn4+ doped Y3Al5O12-YAlO3 phosphors for plant growth lighting

Abstract

Mn⁴⁺-doped Y₃Al₅O₁₂-YAlO₃ phosphor (YAG-YAP:Mn⁴⁺) material was successfully fabricated by a solid-state reaction method, supported by a high-energy planetary ball milling. X-Ray Diffraction Pattern (XRD) analysis result shows that the obtained product consists of two main Y₃Al₅O₁₂ (YAP) and YAlO₃ (YAG) phases when the sample is annealed at higher temperatures of 1300°C. Field Emission Scanning Electron Microscopy (FESEM) and X-ray Energy Dispersion X-Ray Spectrum (EDS) spectra indicate that the high-purity YAG-YAP:Mn⁴⁺ phosphor has a granular form with an average size of about 1-5 μm. By Photoluminescence excitation (PLE) and Photoluminescence spectra investigation, the YAG-YAP:Mn⁴⁺ phosphor, which could be well excited at two wavelengths of 305 and 477 nm, emits strongly in a wide wavelength range from the red light region (674 nm) to the far red region (715 nm). The peaks at 674 and 715 nm are attributed to the ²E→⁴A₂ transition of Mn⁴⁺ ions in the YAG and YAP lattices, respectively. Under the experimental conditions, the highest photoluminescence intensity is found in the YAGYAP:0.2%Mn⁴⁺ sample after annealing at 1300°C for 5 hours in the air. The obtained results suggest that the synthesised YAGYAP:Mn⁴⁺ phosphor material has great potential for application in specialised plant growth LED.