Preparation and characterization of YAG microspheres doped with Eu2+/ Eu3+ for broad band emission

Ghadamyari, M; Klement, R; Hosseini, H. E.; Parchoviansky, M; Kraxner, J; Galusek, D; Narayanasamy, S; Hack, E; Blugan, G; Michalkova, M

doi:10.1016/j.oceram.2024.100654

by European Commission

https://research-and-innovation.ec.europa.eu

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Research and Innovation

Published August 7, 2024 | Version v1

Journal Open

Preparation and characterization of YAG microspheres doped with Eu2+/ Eu3+ for broad band emission

Achieving full-spectrum lighting is a major challenge for phosphor-converted light-emitting diodes (pc-LEDs), which are crucial for solid-state lighting. This study presents the synthesis of polycrystalline Eu-doped Y3Al5O12 (YAG) phosphors through a sol-gel method and flame synthesis process, leading to XRD amorphous microspheres. The amorphous nature of the microspheres allows the reduction of Eu3+ to Eu2+ at a significantly lower temperature (800 ◦C) than the reduction of crystalline samples described in the literature (1400 ◦C). The presence of Eu2+ in the YAG lattice was confirmed by X-ray photoelectron spectroscopy (XPS). The X-ray diffraction (XRD) of samples annealed in reducing atmosphere confirmed partial crystallization of pure YAG in all examined samples. The Eu-doped YAG phosphor embedded in residual glass microspheres exhibited a broadband emission spectrum over the wavelength range 450–800 nm peaking at 565 nm, corresponding to the 4f6 5d1 → 4f7 electron transition within the Eu2+ ions.

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