Development of carbon-60:lithium fluoride nanocomposite electron transport materials for OLEDs.

摘要

Highly conductive charge transport materials have been in great demand to improve organic light emitting diode (OLED) efficiency and operational stability. In this study, C60:LiF nano-composites have been synthesized by physical vapor-phase deposition and studied as electron transport materials in OLEDs. It is found that the nano-composite films are extremely conductive even at high LiF concentrations of up to 75 wt% and that the films form Ohmic contacts with Al electrode. Infrared spectroscopy suggests evidence of charge transfer from LiF to C60. Scanning electron microscope images show that C60:LiF(75%) nano-composites form uniform films at 20nm, the typical thickness used in OLEDs. Compared with pure C 60 based devices, OLEDs with C60:LiF composite electron transport materials have lower driving voltages and higher efficiencies.