Developing solid-state photon upconverters based on sensitized triplet–triplet annihilation

Photon upconversion assisted by sensitized triplet–triplet annihilation (sTTA-UC) is a wavelength-shifting technique where high-energy photons are emitted from the radiative recombination of singlets populated through metastable triplets two annihilator/emitter molecules. The emitter previously via energy transfer light-harvester/sensitizer moiety that absorbs incident low-energy photons. In solutions, this process efficient even at low excitation powers, whereas limited molecular mobility and short exciton lifetimes typically observed in solid matrices hinder bi-molecular interactions making sTTA-UC rather ineffective. We show here controlling confinement upconverting dye pairs nanostructured or nanosized materials results an increased effective local density energy. This also activates specific kinetics independent triplet excitons’ improves material performance powers. provide complete modeling confined systems. obtained afford useful guidelines for future development photonic devices operating subsolar irradiances suitable technological implementation.