Behavioral study of flexible platinum counter electrodes under alternative bending conditions

The electrocatalytic behavior of flexible platinum (Pt) counter electrodes (CEs) is of great importance to practical applications of flexible dye-sensitized solar cells (DSCs). In this study, the electrocatalytic activity of two different flexible Pt CEs with continuous and non-continuous Pt films, which were prepared by a sputtering method and an electroless deposition method, respectively, was studied under alternative bending conditions. The data obtained from electrochemical impedance spectroscopy measurements show that the electrocatalytic activity of the continuous Pt CEs slightly increases with the increasing bending cycles, due to the enhanced bare surface area formed from localized delamination and cracking. In contrast, the non-continuous Pt CEs demonstrate much higher resistance towards bending tests, i.e., their electrocatalytic activity remains unchanged even after 25 000 bending cycles. This can be attributed to the high strain tolerance and unique surface structure for this kind of non-continuous Pt CE, which helps the release of stress during the bending tests.