Nanostructured metal filled porous alumina as an anode in polymer light-emitting diodes

摘要

In real electronic devices the elevated operating temperature of the active medium with respect to the "standard" room temperature (21-23℃) is a direct result of Joule heating and acts as a limiter to device performance and lifetime. It has been shown for discrete devices that as the active area is reduced the device is less susceptible to Joule heating. Therefore smaller devices may be driven at higher current densities for a longer period of time than similar devices with a larger active area. This is important for electronic display applications where the display brightness, which is proportional to current density and the display lifetime, is critical. We report on how a porous alumina membrane, filled with nickel using a pulsed electro-deposition technique, was used as a nano-structured anode in polymer light-emitting diodes. Devices made using mechanically polished nickel-filled membranes were tested. Electrical data are presented and the uniformly filled porous alumina based devices sustained higher current densities, than equivalent conventional evaporated metallic sheet-electrode devices. It was found that the reproducibility and rectification ratios of the uniformly filled nickel devices represent a significant improvement on similar copper-filled devices.