Experimental study on loading-induced power generation decline of component-level flexible solar cells

Flexible solar cells have a promising future to be intergraded with building systems, but the practical potential has been limited by the macroscopic mechanical properties that directly relate to power generation efficiency. In this study, the mechanical–photovoltaic properties of two commercialized flexible solar cells (amorphous silicon and dye-sensitized) were experimentally investigated under standard tensile test and cyclic test. Guided by the mechanical tests and the scanning electronic microanalysis, we found that both amorphous silicon and dye sensitized solar cells showed high strain to initiate the power generation decline in terms of mechanical properties and voltage output, while much lower strain, less than 1.0% strain, in terms of fill factor (FF). In addition, variation on geometry and reinforcing materials in the protection layer might improve stiffness but did not prevent the early initiation of FF decline. Identifying the limitation in flexible solar cells is a critical step for the development of multifunctional structural components, in which flexible solar cells are embedded into curved surfaces of buildings and bridges.