Regensburg 2002 – wissenschaftliches Programm

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SYOH: Organische Halbleiter

SYOH 5: Organic Light-Emitting Devices

SYOH 5.3: Vortrag

Montag, 11. März 2002, 16:45–17:00, H37

VERY-LOW-VOLTAGE ORGANIC SMALL MOLECULE ELECTROLUMINESCENT DEVICES USING PIN-STRUCTURES — •Jingsong Huang, Jan Blochwitz-Nimoth, Martin Pfeiffer und Karl Leo — Institut fuer Angewandte Photophysik, TU Dresden, D-01062 Dresden, Germany

Organic light emitting diodes generally suffer from higher operating voltages compared to inorganic ones. This limits their application in passive or active driven displays based on OLED-technology. As was previously shown by our group, p-type doping of the hole injection and transport layer of an organic light emitting diode (OLED) by co-evaporation of a matrix and an acceptor molecule leads to lower operating voltages of the device.

As a further step towards PIN-structure OLEDs, we have realized a small-molecule organic light emitting diode where the intrinsic emitter layer is sandwiched by n- and p-doped transport layers with appropriate blocking layers. The diodes based on this PIN-concept have exponential forward characteristics up to comparatively high current densities. The diodes reach high brightness at very low operating voltage: for instance, 1000cd/m2 at a voltage of 2.9V, which is the lowest value ever reported for non-polymeric OLEDs. Despite the highly doped transport layers, the devices reach very high efficiency for the given emitter system up to high brightness.