Investigation of Electrical Characteristics Dependency of Roll-to-Roll Printed Solar Cells With Silver Electrodes on Mechanical Tensile Strain

In this work we have studied the effects of the tensile mechanical strain on the electrical behavior of a roll-to-roll printed solar cell module with silver electrodes. After applying the strain along the length of the solar module, its current-voltage curves were measured in dark and under light illumination conditions. By electrical parameters extraction of the curves in both conditions, valuable information was achieved which proved that the dark and light parameters are in good agreement with each other and can each be used as a means to evaluate the solar cells. Electrical parameters like series resistance and power conversion efficiency, all show improvements for moderate tensile strain levels. The power conversion efficiency had about 3.8% improvement after applying 2400 με tensile strain. This is due to the polymer chains alignment in the direction of the applied tensile strain. However, higher strain levels damaged the interfaces among the solar cells' layers. These broken bonds created a high density of defect states and thus reduced the electrical performance of the solar cell. This research showed that the solar cell under the test can be mechanically deformed under moderate strains while showing a better electrical performance. So these cells are a suitable choice for applications in which the cells are used under a mechanical tensile strain.