Effect of extra added Mg2+ and Si4+ on the microstructure and luminescence properties of Ce:YAG ceramic phosphors for high power LED/LD lighting

The study deals with the use of different amounts of MgO or tetraethyl orthosilicate (C8H20O4Si, TEOS), from 0.04 wt %, 0.06 wt %, 0.08 wt %, 0.4 wt %, 0.6 wt % to 0.8 wt %, respectively, as additional sintering aids during the vacuum sintering of transparent Ce3+ doped Y3Al5O12 (Ce:YAG) ceramics to...

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Bibliographic Details
Published in:	Ceramics international 2023-04, Vol.49 (7), p.11311-11322
Main Authors:	Zhang, Qian, Shi, Yun, Kosyanov, Denis, Xiong, Yifei, Wu, Tong, Zhou, ZhenZhen, Liu, Qian, Fang, Jinghong, Ni, Jinqi, He, Huan, Yu, Jianding, Niu, Mingjun, Liu, Wentao
Format:	Article
Language:	eng
Subjects:	Ce:YAG ceramic Phosphors Mg2 Si4 Sintering aids White LED
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Summary:	The study deals with the use of different amounts of MgO or tetraethyl orthosilicate (C8H20O4Si, TEOS), from 0.04 wt %, 0.06 wt %, 0.08 wt %, 0.4 wt %, 0.6 wt % to 0.8 wt %, respectively, as additional sintering aids during the vacuum sintering of transparent Ce3+ doped Y3Al5O12 (Ce:YAG) ceramics to investigate their effect on microstructure and luminescence properties. A comparative study was carried out by using X - ray diffraction, scanning electron microscopy/energy dispersive X - ray spectroscopy, optical and photo-luminesce spectra, as well as electroluminescent spectra. The dominant garnet phase was obtained even when adding 0.8 wt % of MgO or TEOS, while adding MgO led to finer average grain size (∼ 5 - 10 μm) and more homogenous distribution compared to TEOS (∼ 20 - 25 μm) in Ce:YAG ceramics. Adding a large amount of MgO was found to result in the segregation of MgO in Ce:YAG ceramics, while an excess of TEOS led to the segregation of Al2O3. A strong absorption peak at 308 nm was observed in Ce:YAG ceramics with MgO sintering aids, which was ascribed to the existence of Ce4+ induced by a charge compensation effect of Mg2+. The optimum transmittance reached 80% @ 800 nm in Ce:YAG ceramics when adding 0.6 wt % TEOS, which also exhibited a maximum luminous efficacy of 106 lm/W. Si4+ was experimentally proved to have a better optimization effect on luminous efficacy compared to Mg2+. •MgO or TEOS (C8H20O4Si) was added as additional sintering aids in a wide amount range.•MgO proves to have distinct inhibit effect on the grain growth.•Better luminous efficacy were observed in ceramics with TEOS additives.
ISSN:	0272-8842 1873-3956