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DS: Fachverband Dünne Schichten
DS 16: Organic Light Emitting Diodes (SYOE 9)
DS 16.8: Talk
Wednesday, March 28, 2007, 16:15–16:30, H32
Organic light emitting diodes on ITO-free polymer anodes — •Karsten Fehse, Gregor Schwartz, Karsten Walzer, and Karl Leo — Institut für Angewandte Photophysik, TU Dresden, D-01062 Dresden
The high material cost of indium, being the main component of the commonly used indium-tin-oxide anodes (ITO) in organic light emitting diodes (OLEDs), is an obstacle for the production of efficient low-cost OLEDs. Therefore, new anode materials are needed for large scale OLED production. Recently, we demonstrated that the polymer PEDOT:PSS can substitute ITO as anode. Another highly conductive polymer is polyaniline (PANI) that provides 200 S/cm with a work function of 4.8 eV. In this study, we use PANI as anode for OLEDs (without ITO layer underneath the polymer) with electrically doped hole- and electron transport layers and intrinsic materials in between. Fluorescent blue (Spiro-DPVBi) as well as phosphorescent green (Ir(ppy)3) and red emitters (Ir(MDQ)2(acac)) were used for single colour and white OLEDs. Green single and double emission OLEDs achieve device efficiencies of 34 lm/W and 40.7 lm/W, respectively. The white OLED shows a power efficiency of 8.9 lm/W at 1000 cd/m2 with CIE coordinates of (0.42/ 0.39).