title: Importance of spin-orbit interaction for the electron spin relaxation in organic semiconductors.
abstract: Despite the great interest organic spintronics has recently attracted, there is only a partial understanding of the fundamental physics behind electron spin relaxation in organic semiconductors. Mechanisms based on hyperfine interaction have been demonstrated, but the role of the spin-orbit interaction remains elusive. Here, we report muon spin spectroscopy and time-resolved photoluminescence measurements on two series of molecular semiconductors in which the strength of the spin-orbit interaction has been systematically modified with a targeted chemical substitution of different atoms at a particular molecular site. We find that the spin-orbit interaction is a significant source of electron spin relaxation in these materials.
authors.affiliation: Queen Mary University of London, School of Physics and Astronomy, Mile End Road, London E1 4NS, United Kingdom. laura.nuccio@unifr.ch
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authors.lastname: Nuccio
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authors.lastname: Willis
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authors.lastname: Schulz
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authors.lastname: Fratini
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authors.lastname: Purushothaman
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