Enhancement of optical and electrical performance of organic light emitting diodes fabricated by SAM modified ITO anodes

Electrode modification in organic semiconductor devices has attracted much attention in last decade. Among these studies, ITO (Indium Tin Oxide) as an electrode is widely used in organic light emitting diode (OLED) due to its relatively low resistance and high transparency. On the other hand, it has rough surface and low work function compared to the organic molecules used in OLEDs. Since surface roughness limits the hole injection from anode into the hole transport layer (HTL), we have tuned OLED performance by means of a ferrocenecarboxylic acid (FCA) self-assembled mono layer (SAM) through adjusting the interface between ITO and the organic layer. The improvements in current, luminescence and device efficiency of OLED using SAM modified ITO were obtained comparing to OLED devices with bare ITO as anode. The electrical properties of the OLEDs are modeled by using the modified Shockley equation with Lambert W-function. This enhancement on device performance is attributed by better hole injection and smoothness of the layer between ITO and organic layers.