Compositional engineering of phase-stable and highly efficient deep-red emitting phosphor for advanced plant lighting...

Area of Science:

• Materials Science
• Solid-State Chemistry
• Optoelectronics

Background:

• Inorganic luminescent materials are crucial for optoelectronics, but oxide-based deep-red phosphors face limitations in efficiency and thermal stability, hindering plant lighting.
• Current phosphors struggle to meet the specific spectral needs of plant phytochromes, impacting the effectiveness of artificial lighting solutions.

Purpose of the Study:

• To develop a novel oxide-based deep-red emitting phosphor with enhanced efficiency and thermal stability for plant lighting.
• To investigate the impact of compositional engineering on the phase purity, luminescence properties, and thermal robustness of NaMgPO4:Eu phosphors.

Main Methods:

• Compositional engineering by incorporating SiO4 into the PO4 tetrahedron of NaMgPO4:Eu.
• Phase analysis, photoluminescence spectroscopy, and thermal stability testing were employed.
• Fabrication and testing of a phosphor-converted light-emitting diode (pc-LED) device.

Main Results:

• A pure olivine phase was achieved, significantly increasing external quantum efficiency (EQE) from 27% to 52%, a record for oxide deep-red phosphors.
• Thermal stability at 150°C improved from 62.5% to 85.4% due to a deep defect level.
• Optimized excitation (440 nm) and emission (675 nm) peaks align with plant phytochrome absorption, showing minimal decay under humidity and heat stress. A pc-LED achieved 780 mW output power.

Conclusions:

• Compositional modification of NaMgPO4:Eu with SiO4 offers a facile route to high-performance deep-red phosphors.
• The developed material provides a stable, efficient, and spectrally suitable light source for advanced plant lighting.
• This research presents a promising alternative for cost-effective and high-performance horticultural lighting solutions.