Triplet-triplet annihilation upconversion from rationally designed polymeric emitters with tunable inter-chromophore distances

We report an investigation of triplet-triplet annihilation upconversion (TTA-UC) based on polymeric emitters with tunable inter-chromophore distances. Poly[(9-anthrylmethyl methacrylate)-co-(methyl methacrylate)] (poly(AnMMA-co-MMA)) with different percentages of AnMMA was synthesized using reversible addition-fragmentation chain transfer (RAFT) polymerization, and used as an emitter in association with platinum octaethylporphyrin as a sensitizer to form TTA-UC systems. It is observed that the TTA-UC intensity first increases with increasing AnMMA percentage in the polymers then decreases, and ultimately disappears, upon further increasing the AnMMA percentage. The results shed light on the key factors affecting TTA-UC in polymers, and have implications for the design of polymer-based TTA-UC systems.