Three-dimensional chemical and physical analysis of the degradation mechanisms in organic photovoltaics

Insufficient lifetimes of organic photovoltaics are manifested in a reduced photovoltaic response, which is a consequence of physical and chemical degradation of the photovoltaic device. To prevent degradation it is vital to gain detailed insight into the degradation mechanisms. This is possible by utilizing state-of-the-art characterization techniques such as TOF-SIMS, XPS, AFM, SEM, interference microscopy and fluorescence microscopy as well as isotopic labeling (¹⁸O₂ and H₂¹⁸O). By a combination of lateral and vertical analyses of the devices we obtain in-depth and in-plane information on the reactions and changes that take place in the various layers and interfaces. Examples will be presented that describe the advantages and disadvantages of various characterization techniques in relation to obtaining information on the degradation behavior of complete photovoltaic devices.