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.