Triplet–Triplet-Annihilation Upconversion for Photopolymerisation: Sensitiser–Annihilator Pairs, Oxygen, Thresholds and Cure Depth

Triplet-triplet annihilation upconversion (TTA-UC) can convert lower-energy illumination into higher-energy emission that drives photopolymerisation with a nonlinear intensity response. This creates opportunities for cure confinement, visible-light operation and lower-cost optical hardware, but the useful threshold depends on sensitiser-annihilator photophysics, oxygen quenching and initiator coupling. This review links those variables to cure depth, voxel confinement and process stability using high-resolution printing and DLP demonstrations.

ER-303 · Version 0.5.