Open Access Research Article Issue
Composite structure Al2O3/Al2O3–YAG:Ce/YAG ceramics with high color spatial uniformity for white laser lighting
Journal of Advanced Ceramics 2024, 13 (2): 189-197
Published: 01 February 2024
Abstract PDF (2 MB) Collect

Composite ceramic phosphor (CCP) is a candidate light-conversion material to obtain the high-quality laser lighting source. Phosphors based on the transmissive configuration model could not simultaneously meet the requirements of angular color uniformity and high thermal stability. In this study, a novel composite structure ceramic was designed, including Al2O3–YAG:Ce/YAG layered ceramic with a size of 1 mm × 1 mm for lighting, and Al2O3 ceramic (φ = 16.0 mm) was used as the wrapping material due to its outstanding thermal stability. The prepared ceramics exhibited excellent thermal performance and no yellow ring phenomenon. Through this design, we achieved the match of the intensity distribution of the blue and yellow lights, resulting in a high angular color uniformity of 0.9 with a view angle of ±80°. All ceramics showed no luminous saturation phenomenon, even the laser power density was increased up to 47.51 W/mm2. A high-brightness white-light source with a luminous flux of 618 lm, a luminous efficiency of 126 lm/W, a CCT of 6615 K, and a CRI of 69.9 was obtained in the transmissive configuration. In particular, the surface temperature of the ceramic was as low as 74.1 ℃ under a high laser radiation (47.51 W/mm2). These results indicate that Al2O3/Al2O3–YAG:Ce/YAG composite structure ceramic is a promising luminescent material in the high-power laser lighting applications.

Open Access Research Article Issue
Efficient spectral regulation in Ce:Lu3(Al,Cr)5O12 and Ce:Lu3(Al,Cr)5O12/Ce:Y3Al5O12 transparent ceramics with high color rendering index for high-power white LEDs/LDs
Journal of Advanced Ceramics 2021, 10 (5): 1107-1118
Published: 14 July 2021
Abstract PDF (17.4 MB) Collect

Realizing a high color rendering index (CRI) in Ce:LuAG transparent ceramics (TCs) with desired thermal stability is essential to their applications in white LEDs/LDs as color converters. In this study, based on the scheme of configuring the red component by Cr3+ doping, an efficient spectral regulation was realized in Ce,Cr:LuAG TCs. A unilateral shift phenomenon could be observed in both photoluminescence (PL) and photoluminescence excitation (PLE) spectra of TCs. By constructing TC-based white LED/LD devices in a remote excitation mode, luminescence properties of Ce,Cr:LuAG TCs were systematically investigated. The CRI values of Ce:LuAG TC based white LEDs could be increased by a magnitude of 46.2%. Particularly, by combining the as fabricated Ce,Cr:LuAG TCs with a 0.5 at% Ce:YAG TC, surprising CRI values of 88 and 85.5 were obtained in TC based white LEDs and LDs, respectively. Therefore, Ce,Cr:LuAG TC is a highly promising color convertor for high-power white LEDs/LDs applied in general lighting and displaying.

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