Subsequent projects

Prof. Dr. Wolfgang Brütting
University of Augsburg
Lehrstuhl für Experimentalphysik IV

Prof. Dr. Mark E. Thompson
University of Southern California,
Los Angeles
Department of Chemistry

Understanding molecular orientation in phosphorescent OLEDs

Organic light-emitting diodes (OLEDs) using metal-organic Iridium complexes show efficient phosphorescence, however, only a small fraction of the internally produced optical energy can actually be extracted as visible light. This fraction can be significantly increased, if the transition dipole moments of the dye molecules have a preferential orientation in the film plane.

The goal of this joint project is to understand the microscopic mechanism of molecular orientation in phosphorescent guest-host systems and to demonstrate its applicability in OLEDs. We will combine the complementary expertise of both groups in synthesis of model compounds and optoelectronic characterization of devices, respectively, to achieve a better understanding of the underlying effects.

Primary project: Influence of molecular orientation in organic optoelectronic devices

Final Report

Within the BaCaTeC funded collaboration between the groups at Augsburg University and the University of Southern California we studied organic light-emitting diodes (OLEDs) based on phosphorescent metal-organic Iridium complexes. The focus was on clarifying the orientation mechanism of guest-host systems with these dyes as emitter material in OLEDs. We have been able to show that alignment is controlled by two factors: the ligand sphere of the complex [1], and the deposition conditions of the emission layer [2]. The current understanding of emitter alignment and its relevance for device applied in OLEDs are summarized in an invited review article published in Physical Review Applied [3]. Additionally, we have reported on results of organic photovoltaics that were created during the first project phase.


  1. Understanding and Predicting the Orientation of Heteroleptic Phosphors in Organic Light-Emitting Materials, M. J. Jurow, C. Mayr, T. D. Schmidt, T. Lampe, P. I. Djurovich, W. Brütting, M. E. Thompson, Nature Materials 15 (2016) 85-91; DOI: 10.1038/nmat4428
  2. Dependence of Phosphorescent Emitter Orientation on Deposition Technique in Doped Organic Films, T. Lampe, T. D. Schmidt, M. J. Jurow, P. I. Djurovich, M. E. Thompson, W. Brütting, Chem. Mater. 28 (2016) 712–715; DOI: 10.1021/acs.chemmater.5b04607
  3. Emitter Orientation as a Key Parameter in Organic Light-Emitting Diodes, T. D. Schmidt, T. Lampe, D. Sylvinson M. R., P. I. Djurovich, M. E. Thompson, W. Brütting, Phys. Rev. Applied 8 (2017) 037001; DOI: 10.1103/PhysRevApplied.8.037001
  4. Organic Solar Cells with Open Circuit Voltage over 1.25 V Employing Tetraphenyldibenzoperiflanthene as the Acceptor, A. N. Bartynski, S. Grob, T. Linderl, M. Gruber, W. Brütting, M. E. Thompson, J. Phys. Chem. 120 (2016) 19027−19034; DOI: 10.1021/acs.jpcc.6b06302


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