ABSTRACT
In all organic semiconductor (OSC) devices, the charge transport process across interfaces of dissimilar materials is important for optimum device operation. For organic photovoltaic (OPV) cells, the most fundamentally important process is the charge transfer (CT), or interfacial dissociation of excitons at the donor–acceptor interface. It is critical to have efficient charge transport across the interfaces, whether between the organic or inorganic multiplayer structures, or with the electrodes. This chapter is intended to introduce the reader to the field by providing some insights through examples of different aspects of the interface formation, mostly taken from the author's own experience using surface analytical tools for the investigations. Examples include the mechanisms of interface dipole formation for the explanation of asymmetry in I–V characteristics for interfaces of the same metal and organic material, but formed differently by either metal deposition on organic or organic on metal, the treatment of indium tin oxide (ITO) and other forms of interface engineering, the interface formation and energy level alignment of organic–organic interfaces, and the charge transfer dynamics between donor and acceptor layers.
