Investigation of the solvent influence on polymer–fullerene solar cells by low frequency noise spectroscopy

The electron density of states and recombination kinetics of bulk heterojunction solar cells have been determined by means of low-frequency noise spectroscopy at room temperature and in dark conditions. The observed differences in the disorder parameter and electron lifetime are attributed to a different film ordering of the active layer because of the influence of a solvent additive. Blends prepared with the reference solvent resulted in the lowest electron lifetime and density of states population, while blends prepared with the addition of a high boiling point solvent resulted in a more efficient charge carrier separation and a higher electron lifetime.