Spin transport in organic semiconductor single crystals

Organic semiconductors have been attracting much attention as potential spin transport media due to their weak spin-orbit and hyperfine interactions that promise long spin lifetimes. However, to date most studies have focused on amorphous, or polycrystalline thin-film based organic semiconductors. In addition, short transport distances equal to or less than a couple of hundred nanometers have been measured despite the prediction of long spin transport distance. We have investigated spin injection and transport in high purity single-crystal organic semiconductors, especially rubrene(5,6,11,12-tetraphenylnaphthacene). We will present and discuss our experimental results obtained in both vertical and lateral transport geometries. Great care is needed to understand and avoid possible spurious effects in these studies.