Interface Structure and Emission Efficiency of Polymeric Light Emitting Diodes

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9303019 Gao This research addresses surface and interfacial phenomena in polymeric light emitting diodes (LEDs). The objectives are to understand the electronic states involved in electroluminescence and the electronic and chemical structure of polymer/metal interfaces. Coordinated experimental studies of the interface formation of poly(phenylene vinylene)PPV and a selection of metals using x-ray photoemission spectroscopy (XPS), inverse photoemission spectroscopy (IPES), electroluminescence spectroscopy (ELS), and other surface sensitive probes will be conducted. The combination of XPS and IPES in the same ultra-high vacuum (UHV) system allows probing of both occupied and unoccupied electronic structures independently and simultaneously. Concurrent measurement of ELS is expected to reveal relationships between light emission efficiency and interface electronic structure and chemistry. %%% This research is expected to provide fundamental information useful for the future development of polymer based flat panel display technologies. Parameters of practical interest such as the thicknesses of the polymer and metal layers, different degrees of conversion and different types of light emitting polymers, and the stability of the LEDs will be investigated. The project combines expertise in surface physics and polymer chemistry, and is a joint effort between university and industrial research scientists. The interdisciplinary nature of the project and the academic and industrial collaboration is expected to uniquely benefit students and enhance the transfer of knowledge from university to industry. ***