Principal Investigator Yang Shao-Horn
Knowing and controlling the surface composition of perovskite is crucial to enhance device performance. We demonstrated that the surface strontium (Sr) and cobalt (Co) concentrations of perovskite-based thin films can be controlled reversibly at elevated temperatures by applying small electrical potential biases. The surface compositional changes of La0.8Sr0.2CoO(3–δ) (LSC113), La0.5Sr0.5)2CoO(4±δ) (LSC214), and LSC214-decorated LSC113 films (LSC113/214) were investigated in situ by utilizing synchrotron-based X-ray photoelectron spectroscopy (XPS), where the largest changes of surface Sr was found for the LSC113/214 surface. These findings offer the potential of reversibly controlling the surface functionality of perovskites.