Sensitized triplet–triplet annihilation upconversion (sTTA-UC) can convert two low-energy photons into one of higher energy, but its use in water is often limited by the poor solubility of the required chromophores. Researchers from the RTG2900 overcome this challenge by encapsulating a red-to-blue upconversion pair in water-stable ~100 nm polystyrene nanoparticles. Under red light irradiation, these nanoparticles act as efficient heterogeneous photocatalysts that drive radical polymerization of acrylate monomers in water, forming polymer gels with nearly quantitative conversion.
This work has been published in Advanced Optical Materials in February 2026:
Red-to-Blue Upconversion Nanoparticles Catalyze Aqueous Radical Polymerization
Daniella Hübner, Cuong Minh Quoc Le, Arnaud Spangenberg, Pengyue Jin, Cui Wang
