EPR characterization of catalyst-free SWNT and N@C60-based peapods

Single Wall Carbon Nanotubes (S &INT) produced by "Super-Growth" CVD technique show no evidence for non-carbon impurities. At X-Band frequencies an EPR signal from conduction electrons is observed at room temperature. At low temperatures the conduction electrons get trapped, leading to a sharp EPR signal with long-lived spin states. Using multi pulse techniques the hyperfine interaction to C-13 can be resolved. Using low temperature liquid phase filling techniques, it is possible to prepare N@C-60@SWNT with filling efficiencies of a few percent. At elevated temperatures, the fullerenes show a quite mobile behavior, especially in SWNT of wide diameter. This motion continuously slows down at lower temperatures resulting in complete immobilization. (c) 2006 WILEYNCH Verlag GmbH & Co. KGaA, Weinheim.