Cyan-green-emitting Ca ₃Sc ₂Si ₃O ₁₂:Ce ³⁺ transparent ceramics: A promising color converter for high-brightness laser lighting

Abstract

Transparent phosphor ceramics have received increasing attention for high-brightness laser lighting, but commercially available phosphor ceramics are currently mainly limited to 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 3 Sc 2 Si 3 O 12 :Ce 3+ (CSS:Ce) transparent ceramics have been successfully developed by two-step sintering technique under vacuum. The as-prepared CSS:Ce ceramics present high relative density of 99.7% and 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 internal/external quantum efficiency of 91%/62%. Furthermore, it has excellent thermal stability with a thermal quenching temperature (T 0.5 ) of 838 K, approximately 100 K higher than that of LuAG:Ce ceramics (738 K). In addition, the CSS:Ce ceramics can withstand blue laser density of 45.6 W/mm 2 and meanwhile generates cyan-green light with a forward luminous flux of 813 lm and forward luminous efficacy of 162 lm/W. The CSS:Ce transparent ceramics exhibit excellent luminescence performance comparable to the commercial LuAG:Ce ceramics and could be a highly promising color converter for high-brightness laser lighting.

Ce:(Lu,Sr)3(Al,Si)5O12 transparent ceramics for high-power white LEDs/LDs with ultra-high luminance saturation threshold

“…White light emitting diodes or laser diodes (WLEDs/WLDs) have attracted significant attention for their environmentally friendly nature, small volume and long service life. 1–16 Currently, the main method for constructing WLEDs/WLDs is to combine a blue LED/LD chip or a blue laser source with a Ce 3+ :Y 3 Al 5 O 12 (Ce:YAG) material. 17,18 However, phosphors encapsulated by the traditional organic resin have low thermal conductivity (0.1–0.4 W m −1 K −1 ), and are easy to burn or carbonize at high temperatures, which are not suitable for high power LED or LD lighting.…”

High recorded color rendering performance of single-structured Ce,Mn:Y 3(Al,Sc) 2Al 3O 12 phosphor ceramics for high-power white LEDs/LDs

“…Ce:YAG PCs are considered to be the potential conversion materials. Nevertheless, white LED/LDs structured by traditional Ce:YAG PCs still suffer from a low color rendering index (CRI＜60) and highly correlated color temperature (CCT＞7500 K) due to the lack of spectral components both in red and cyan areas [1,[14][15][16][17][18][19]. Many optimized PCs usually have the problem of luminous declining under high power density excitation.…”