Study of lanthanum-based cathode materials for organic light-emitting devices.

Abstract

Since the dawn of the information age, the high technology industry has been driven to display more data and to create large area high-resolution displays. Organic light emitting diodes, introduced in the late 1980s, are emerging as an attractive alternative to other display technologies. These devices offer cheap materials, low operating voltages, high brightness and a wide viewing angle. The ability to spin coat molecular materials on large rigid or flexible substrates is unparalleled in existing technologies. Several different device geometries are possible, ranging from the simple homostructure, where there is only one organic material present, to the complex microcavity, where dielectric stacks are used to selectively filter out specific wavelengths of light. No matter which geometry is chosen, all of these devices have several common features: a high work function anode (usually transparent) and a low work function cathode. Due to the low work function requirement of the cathode, we are limited to the very reactive metals in the periodic table. In this thesis cathodes based on pure lanthanum, lanthanum-silver bilayers, and lanthanum-yttrium alloys were investigated. (Abstract shortened by UMI.)