Characterization of polymer: fullerene solar cells by low-frequency noise spectroscopy

A detailed electric noise investigation of polymer:fullerene solar cells, at 300 K under dark conditions, is reported. The experimental noise results are interpreted in terms of a model taking into account the device capacitance and recombination resistance. Relevant parameters of the solar cells can be computed through fluctuation spectroscopy, and the results have been compared with those obtained by alternative techniques. After a thermal treatment at 340 K, a modification of the voltage-spectral traces has been observed and related to a strong cell resistance reduction.