Effects of mechanical strain on the performance of amorphous silicon triple-junction solar cells

Amorphous silicon triple-junction solar cells were tested in tension and compression. The production cells had the structure: stainless steel (125 μm)/Al/ZnO/n₁i₁p₁n₂i₂p₂n₃i₃p₃/ITO/grid, where i₁ and i₂ are a-SiGe:H and i₃ is a-Si:H. We bent the solar cells to strains as high as 2%. The I-V characteristics of the cells were tested before, during and after bending. We found that there was little deterioration in cell performance under compression up to 1.7% strain, which is the physical limit of our experiment. In tension, some cell characteristics began to degrade at strains of 0.75%. Plastic deformation was observed at strains of 0.2% and higher.