Berlin 2001 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 19: Poster: New Methods, Thin Polymer Films, Monolayers
CPP 19.1: Poster
Donnerstag, 5. April 2001, 12:30–15:00, AT1
Scanning Electroluminescence Microscopy (SELM), Combinatorial Study of OLEDs — •Helmut Hänsel1, Heiko Zettl1, Armin Knoll1, Georg Krausch1, Stefan Berlep2, Anton Mückl2, Wolfgang Brütting2, Christoph Schmitz3, Mukundan Thelakkat3, and Hans-Werner Schmidt3 — 1Universität Bayreuth, Physikalische Chemie II — 2Universität Bayreuth, Experimentalphysik II — 3Universität Bayreuth, Makromolekulare Chemie I
A new method for local investigation of charge transport and electroluminescence in OLEDs has been developed. We modified a Scanning Near-field Optical Microscope such, that a Platinum tip could be used as scanning probe similar to conventional STM. To provide additional information on the topography we use shear force detection. At each point we scan the distance of the tip while detecting shear force, current and electroluminescence. Electroluminescence typically starts when the tip is indented several nanometers into the sample and increases with further indentation.
Secondly, we present the testing of multi-layer OLEDs with a systematic thickness variation of the layers. Two gradients of two different materials (e.g. Alq3, DiMeOTPD) are evaporated onto a square ITO-glass substrate. Evaporation of 8x8 Al-elctrodes leads to 64 different diodes. The diodes are simultaneously tested for long-term stability: the development of the electroluminescence- and IV-curves is recorded and optimum film thickness combinations can be determined.