PhD thesis - Evans Research Group - University of Wisconsin-Madison

1Chapter 1Introduction1.1 Organic/inorganic interfaces in organic electronicsOrganic electronics have been aggressively studied for applications in electronic displays,sensors, radio frequency identification tags, smart cards and organic solar cells [1]. Thislarge range of possible applications can be realized by understanding the basic science ininvolved in the operation of organic electronic devices and the physics of organicsemiconductors.Interfaces in organic electronic devices such as organic field effect transistors (OFETs),organic light emitting diodes (OLEDs) and organic photovoltaics (OPVs) take part incharge injection and transfer which are crucial for operating devices. For example, thecathode and anode layers form contacts to an electron transport and hole transport layer [2-6]. The alignment of molecular energy levels between the electrodes and the transportlayers can be tuned by attaching self assembled monolayers (SAMs) to the metalelectrodes. The SAMs can alter the electrostatic potentials at the interface between metaland organic semiconductors and thus control the injection barrier to the organicsemiconductors [7-10].Photoinduced charge transfer between electron acceptor and donor layers is critical indetermining power conversion efficiency in OPVs [11-13]. In these devices, the absorptionof light produces excitons in the electron donor layer that are subsequently dissociated at