Spin-dependent processes in organic and other carbon based semiconductors

Organic and other carbon based semiconductors are materials with weak spin-orbit coupling which makes spin important for electronic transitions that determine the electrical, optical and magnetic properties of these materials. As spin-dependent transport and recombination can determine efficiency limits of organic light emitting diodes and organic solar cells, a thorough qualitative and quantitative knowledge of these effects is crucial for an optimization of these technological applications.

We use electrically and optically detected coherent electron spin resonance techniques in order to investigate spin-dependent processes in OLED and organics solar cell materials. Similar as for inorganic materials, the investigation of coherent spin control mechanisms of electric currents may also ultimately lead to organic spin electronics and quantum information devices.

The figure shows the imprint of a coherent spin rabi nutation of polaron pairs in an MEH-PPV light emitting diode during the application of resonant spin resonant excitation.

Our work on organic semiconductor materials is done in collaboration with the University of Utah Nanooptics group.

Our recent results on this topic:

D. R. McCamey, K. J. van Schooten, W. J. Baker, S.-Y. Lee, S.-Y. Paik, J. M. Lupton*, and C. Boehme*
Hyperfine-field mediated spin beating in electrostatically-bound charge carrier pairs
Phys. Rev. Lett. 104, 017601 (2010).

C. Boehme*, D. R. McCamey, K. J. van Schooten, W. J. Baker, S.-Y. Lee, S.-Y. Paik, J. M. Lupton
Pulsed electrcially detected magnetic resonance in organics semiconductors
Phys. Stat. Sol B. 246, 11-12, 2750 (2009).

D. R. McCamey, H. A. Seipel, S. Y. Paik, M. J. Walter, N. J. Borys, J. M. Lupton* and C. Boehme*
Spin Rabi flopping in the photocurrent of a polymer light-emitting diode
Nature Materials, 7 (2008).

J. M. Lupton*, C. Boehme*
Magnetoresistance in organic semiconductors
Nature Materials, 7, 598 (2008).

Principal Investigator: Christoph Boehme, Department of Physics and Astronomy, University of Utah,
115 S 1400 E, Salt Lake City, UT 84112-0830, phone 801.581.6806 fax 801.581.4801,
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