Fabrication of Organic Light Emitting Diodes in an Undergraduate Physics Course

Thin film organic light-emitting diodes (OLEDs) represent the state-of-the-art in electronic display technology. Their use ranges from general lighting applications to cellular phone displays. The ability to produce flexible and even transparent displays presents an opportunity for a variety of innovative applications. Science and engineering students are familiar with displays but typically lack understanding of the underlying physical principles and device technologies. We believe that OLEDs provide a valuable context in which to engage science and engineering students in the study of electronic devices. Colleges and universities typically do not have the resources available for students to produce working electronic devices like diodes or transistors made from semiconductors like silicon. This paper will describe how science and engineering students, in an upper-level undergraduate physics course, fabricate OLEDs. The active layers of the OLEDs are spin-coated onto glass substrates containing a transparent conductive coating. The cathode is formed by the deposition of an appropriate metal contact layer. The deposition and measurement equipment is relatively inexpensive and can be adopted for use in undergraduate physics or engineering courses; as such we believe the topic will be of broad interest to the physics and engineering community. The paper will discuss the synthesis of the polymer compounds and the associated deposition techniques. Properties of the devices, including current-voltage characteristics, will be presented along with future plans for the development of flexible structures on plastic substrates.