Solvent polarity nearly triples energy transport in organic semiconductors Changing solvent polarity reshapes charge-transfer pathways, extending exciton diffusion nearly threefold without altering the semiconductor’s molecular structure. When plants absorb sunlight to generate energy, they rapidly separate and transfer charge within their internal structures. In solvents with low polarity, such as oil, charge transfer was driven by quantum mechanical tunneling (a quasi-classical regime), in which molecules pass through energy barriers via subtle vibrations. In solvents with high polarity, such as water or alcohol, charge transfer was instead governed by the collective fluctuation of surrounding solvent molecules (a classical regime). This opens a pathway for energy within organic semiconductors to be transferred more efficiently over longer distances without loss.