Changchun Institute of Optics and Mechanics has developed blue-green fluorescent transparent ceramics for laser lighting, laying a key fluorescence material foundation for full color laser lighting

The project of the National Natural Science Foundation of China (Jilin Province) "Multicolor Transparent Silicate Garnet Fluorescent Ceramics for Laser Lighting" presided over by Zhang Jiahua, a researcher in the State Key Laboratory of Luminescence and Applications of Changchun Institute of Optics and Fine Mechanics, has made breakthrough progress, developed green fluorescent transparent ceramics, filled the international gap, and laid a foundation for key fluorescent materials for full-color laser lighting.

The research results are titled "Cyan green mitting Ca3Sc2Si3O12: Ce3+transparent ceramic: a promising color converter for high brightness laser lighting" and published in the top international ceramic journal "Journal of Advanced Ceramics" (2023, 12 (9): 1731-1741)

Laser driven fluorescent transparent ceramics are the preferred solution for obtaining high brightness laser lighting sources, which have urgent needs in automobiles, film and television, and search and rescue lighting. At present, the available fluorescent transparent ceramics for laser illumination are limited to two types of aluminate garnet, yellow YAG: Ce and green LuAG: Ce, which cause incomplete color of the light source and poor color restoration. The lack of cyan is the root cause of these problems, known as the "cyan cavity".

To address the above issues, the project team selected high-efficiency green fluorescent Ca3Sc2Si3O12: Ce3+(CSS: Ce) silicate garnet for ceramic research. In response to the bottleneck of ceramic densification caused by low silicon ion diffusion coefficient, a two-step sintering strategy based on sintering kinetics was proposed, and high-quality green fluorescent transparent ceramics were successfully obtained. Ceramics are suitable for blue light excitation, with a transmittance of 71% at the emission wavelength, an internal quantum efficiency of 91%, a fluorescence quenching temperature of 838 K, and an anti irradiation density of 45.6 W/mm2. At this excitation density, the forward lumen efficiency is 162 lm/W.

The above excellent performance can be comparable to the current commercial YAG: Ce and LuAG: Ce fluorescent transparent ceramics, fully indicating that CSS: Ce silicate garnet fluorescent transparent ceramics are ideal blue-green fluorescence conversion materials for laser lighting, and will play an irreplaceable role in filling "blue-green voids" to achieve full color laser lighting, with broad application prospects.

(a) CSS: Emission spectra of Ce green fluorescent transparent ceramics, transmission spectra, and images under sunlight and blue light; (b) Under the excitation of high-density blue laser, the stable output of lumen flux over time, high brightness blue-green fluorescence images, and temperature distribution maps of ceramic chips, with a maximum temperature of 239 ℃, demonstrate excellent heat resistance.

Source: Sohu