Green Solvent Selection for Green-to-Blue Upconversion Based on TTA

Triplet-triplet annihilation photon upconversion (TTA-UC) of an organic molecular dye pair, 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphyrin platinum(II) (PtOEP) and 1,3,6,8-tetraphenylpyrene (TPPy), has been studied in a wide range of green solvents (alcohols, esters, carbonates, ketones, aromatics, ethers, and dipolar aprotic). UC is important for the study of energy-transfer reactions where the solvent plays a crucial role. To design and process materials for future real applications, growing attention is directed to the use of green solvents, while UC with a few exceptions is generally studied using classic toxic media. In this contribution, the results obtained demonstrate that several green solvents can be valuable options to replace classic toxic counterparts, allowing the photon upconversion with efficient quantum yields also compared to a traditional solvent such as toluene. These results pave the way for the development of a more sustainable TTA-UC system as an effective tool to direct the design of modern green photovoltaic and photocatalytic reactions.