Higher efficiency and longer lifetime for organic light-emitting diodes
Thursday 14 June 2012
The Advanced Technology Institute (ATI) at the University of Surrey working with colleagues from Italy and UCL have shown an increase of 50% in the external quantum efficiency of OLEDs by inserting a PTFE layer within the OLED structure.
The thin layer of chemically-inert fluoropolymer PTFE between the electrode conductor and active electroluminescent material, improves the electrical charge balance in the light-emitting device by manipulating the energy levels within the structure via superficial dipoles which also helps improve device longevity without compromising the total light output.
Prof Ravi Silva, Director of the Advanced Technology Institute, commented “Organic materials are attractive for electronics due to their ability to produce large area, flexible and – in some cases – transparent devices for comparatively little cost. However, the conversion efficiency from electrical to light energy is still low compared to more established and more expensive technologies. In this context, the present research is particularly relevant and represents an important milestone in advancing the state of the art of OLEDs closer to the lifetimes and efficiencies necessary for real-world applications.”
The authors expect further improvements to be possible through the use of other types of fluoropolymer or through modified fabrication techniques, which are new in progress.
The paper reporting this work in Organic Electronics is available for download online: doi:10.1016/j.orgel.2012.02.019.