Composite ceramic with high saturation input powder in solid-state laser lighting: Microstructure, properties, and luminous emittances

Solid-state laser lighting produced by blue laser diode (LD) and yellow-emitting phosphor converter materials is an exciting new development. The great flux from the laser diode results in self-heating, which lead to high temperature, thus new phosphor geometries are required. In this paper, the Al2O3-YAG: Ce phosphor ceramics with high saturation input powder were prepared by spark plasma sintering (SPS). The phase fraction, microstructure, and luminescent properties of ceramics with varying composition were investigated. High luminous emittance (1888 lm/mm(2)) could be reached when the composite phosphor ceramics was applied in laser lighting. In our work, high thermal conductivity, high quantum efficiency, and suitable transmittance play a vital role to obtain ceramic with high saturation input powder. In addition, for the evolution of microstructure, a new model has been established to foretell the thermal conductivity.