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

Abstract

In real electronic devices the elevated operating temperature of the active medium with respect to the "standard" room temperature (21-23ºC) 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.

The fabrication and surface functionalization of porous metal frameworks – a review

“…Through altering the bath conditions the deposition rate can vary between a few nanometres to a few hundred microns an hour. The versatility of electro-less deposition has allowed a number of porous substrates to be efficiently plated including polymer surfaces [90][91][92][93] , carbon fibres 94 , metal surfaces and particles 34,95 , carbon nanotube surfaces 96 , glass 97,98 or porous ceramics (silica, alumina, titania) 35,[99][100][101][102] . Gold and metal nanotube membranes have been fabricated through this approach and used for electrode fabrication 103 , molecular separation 100,104 , lithography, 105 and sensing 13,106 .…”