Investigation of the tensile strain influence on flicker noise of organic solar cells under dark condition

In this paper for the first time low-frequency noise spectroscopy is used as a reliability measure to analyze the organic solar cells under mechanical strain. Two different organic solar cells were strained in several steps and noise spectroscopy was performed on them in dark condition and the defect states and their behavior against the tensile strain were experimentally studied. A test structure to induce the uniform tensile strains on the cells was designed and implemented in a simple and inexpensive noise measurement setup by the authors. The tested solar cells are commercial organic solar cells available on the market. Final results are in complete agreement with the models proposed previously in the literature and showed that the solar cells' behavior after strain is highly dependent on the electrode type. In the solar cell with silver electrodes, a strain lower than 12000 mu epsilon improves the cell's conductivity and thus reducing the flicker noise but it works contrariwise for the cells with carbon nanotube electrodes.