Cyan-green-emitting Ca <sub>3</sub>Sc <sub>2</sub>Si <sub>3</sub>O <sub>12</sub>:Ce <sup>3+</sup> transparent ceramics: A promising color converter for high-brightness laser lighting
Huajun Wu, Hao Wu, Guohui Pan, Liangliang Zhang, Zhendong Hao, Jiahua Zhang
Abstract
Transparent phosphor ceramics have been received increasing attention for high-brightness laser lighting, but the commercially available phosphor ceramics are currently mainly limited to the yellow YAG:Ce and green LuAG:Ce garnets, leaving a “cyan cavity” which is an obstacle to realizing full-color lighting. Achieving new phosphor ceramics capable of filling the cavity is a challenge. Herein, for the first time, cyan-green-emitting Ca<sub>3</sub>Sc<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>:Ce<sup>3+</sup> (CSS:Ce) transparent ceramics have been successfully developed by a two-step sintering technique under vacuum. The as-prepared CSS:Ce ceramic presents a high relative density of 99.7% and an optical transmittance of 71 % in the cyan-green spectral region. It exhibits an efficient band emission peaking at 504 nm (under 450 nm excitation) with an internal/external quantum efficiency of 91%/62%. Furthermore, it has an excellent thermal stability with a thermal quenching temperature (T<sub>0.5</sub>) of 838 K, approximately 100 K higher than that of LuAG:Ce ceramics (738 K). In addition, the CSS:Ce ceramic can withstand a blue laser density of 45.6 W/mm<sup>2</sup> and meanwhile generates cyan-green light with a forward luminous flux of 813 lm and a forward luminous efficacy of 162 lm/W. The CSS:Ce transparent ceramic exhibits excellent luminescence performance comparable to commercial LuAG:Ce ceramics and could be a highly promising color converter for high-brightness laser lighting.