DLP-printed YAG:Ce phosphor ceramics with geometry-enhanced light extraction and heat dissipation

YAG:Ce phosphor ceramics are important color converters for high-power LED lighting. Vat photopolymerization enables complex ceramic geometries, but mixed oxide systems require control of slurry stability, reactive densification, and structure-property relationships. YAG:Ce ceramics were fabricated by digital light processing (DLP) using reactive oxide precursors. A co-dispersant strategy produced a stable photocurable suspension with 51 vol% solid loading, supporting reliable printing. Optimized air calcination regulated precursor reaction and densification, giving vacuum-sintered ceramics with a dense microstructure, low porosity (0.03%), and high in-line transmittance (78.48% at 600 nm, 0.8 mm thickness). A hill-array ceramic was further fabricated. Compared with the flat counterpart of equivalent volume, the structured surface improved heat dissipation and light extraction, reducing peak temperature (by 37.5 °C at 90 W) and increasing luminous efficacy (from 172.02 to 185.54 lm/W at 50 W). These results indicate the potential of DLP-fabricated ceramics as color converters for high-power LED lighting applications.