Regensburg 2002 – wissenschaftliches Programm
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SYOH: Organische Halbleiter
SYOH 7: Poster
SYOH 7.27: Poster
Montag, 11. März 2002, 18:00–21:00, C
Time-of-flight (TOF) measurements on mixtures of low molecular weight organic hole conductors to study trapping effects — •Claus Jäger1, Thomas Susdorf1, Matthias Fischer1, Dietrich Haarer1, and Mukundan Thelakkat2 — 1Experimentalphysik IV — 2Makromolekulare Chemie I and BIMF, Universität Bayreuth, Universitätsstraße 30, 95447 Bayreuth
The mechanism of charge carrier trapping in organic transport materials is still not fully understood. In our studies we generated defined trap states by preparing binary mixtures of low molecular weight hole transport materials (TPDs) with different HOMO levels. The transport properties were investigated by the time-of-flight (TOF) technique, where a short laser pulse of strongly absorbed light generates a delta shaped charge distribution. The charges travel in an applied external electrical field through the bulk material. From the decay of the measured deviation current one can determine the mobility and some transport properties of the material.
A strong variation of the mobility can be seen even for small trap concentrations. The results will be discussed in the frame of known standard models.