Selective Sorting of Semiconducting C70@Single‐Walled Carbon Nanotube Heterostructures with Narrow Diameter Distribution

Abstract Consistently arranging molecules within single‐walled carbon nanotube (SWCNT) templates shows promise for creating advanced 1D heterostructures, but diameter variations in raw SWCNTs pose a significant challenge. In this work, a precise synthesis of C 70 fullerene‐filled SWCNTs (C 70 @SWCNTs) is achieved through vapor‐phase filling followed by polymer sorting. As the SWCNT diameter increases, C 70 molecules first stack in a single chain, then form unusual configurations, including staggered double chains and double helices—configurations not observed in bulk C 70 crystals. SWCNT deformation, which is often overlooked in previous theoretical works, is found to significantly alter the C 70 stacking configuration. C 70 ‐SWCNT electronic interactions, particularly charge transfer, allow selective extraction of C 70 @SWCNTs with narrowly distributed diameters and good semiconducting purity. The sorted C 70 @SWCNTs have diameters of 1.3–1.4 nm, corresponding to C 70 ‐SWCNT distances of ca. 0.34 nm, where the strongest electronic interactions occur. An on/off current ratio of 10⁴ is achieved in their field‐effect transistors. The synthesis and separation strategy sheds light on the preparation and application of 1D heterostructures.