Abstract

To motivate the significance of triplet charge interactions I will briefly introduce recent progress in solution processed phosphorescent organic light-emitting diodes (OLEDs). In contrast to small organic molecule devices, complete modelling of the devices is lacking due to missing rate constants for a variety of dynamic processes in solution based OLE Ds. We developed a method based on time-resolved gated spectroscopy to investigate triplet charge interactions. I will present our study of triplet charge interactions in unipolar devices of polymers and small molecules doped with Pt(II)- of Ir(III)-complexes. To quantify interaction processes it is essential to obtain space-charge-limited currents. From our measurements we extract the mobility which is in good agreement with independent time-of-flight studies. It will be shown how matrix and complex structure influence the rate constant for triplet-charge interaction. At the end I will show results on the magnetic field influence on triplet charge interactions which might give some insight to understanding of organic magnetoresistance effects.