Ce3+-based phosphor converter enabling laser lighting to attain both high CRI and high luminous efficacy

Eu 2+ doped-CaAlSiN 3 possesses broad red emission, enabling a phosphor-converted lighting device to achieve a high color rendering index (CRI) and proper color temperature. However, CaAlSiN 3 :Eu 2+ exhibits relatively slow decay (∼1 μs) and intense re-absorption of luminescence from green/yellow emitters, thereby causing optical saturation and reducing the luminous efficacy. Here, we fabricated a novel phosphor converter comprising Lu 3 Al 5 O 12 :Ce 3+ and Y 1.3 Gd 1.6 Al 5 O 12 :Ce 3+ powders. The typical sample, when excited by a blue laser , exhibited a high luminous efficacy of 231 lm/W and a high saturation threshold of 22.2 W/mm 2 , resulting in a high luminous exitance of 695 lm/mm 2 . Importantly, the phosphor converter produced a broad emission band that included sufficient cyan and red components, resulting in a full width at half maximum (FWHM) of 134 nm and a high CRI of 81. With this excellent balance between CRI and luminous efficacy, the reported phosphor converter can significantly expand the range of laser lighting applications.