fig3

Figure 3. Elemental filling examples: (A) HR-TEM images and schematic illustrations of the chains of iodine filled in SWCNTs (Reproduced with permission^[76]. Copyright 2007, American Chemical Society). (B) The phase transition of iodine from atomic chains to crystalline structures (Reproduced with permission^[76]. Copyright 2007, American Chemical Society). (C) High magnifying STEM ADF image of Te-filled CNTs (Reproduced with permission^[77]. Copyright 2020, Springer Nature). (D) HR-TEM image and simulated diagram of Eu’s single chain filled in DWCNTs (Reproduced with permission^[48]. Copyright 2009, Wiley). (E) TEM image of Sn nanowire formed in CNTs (Reproduced with permission^[15]. Copyright 2016, Elsevier). (F) LLCC@DWCNT Partial HRTEM images of heterogeneous structures. Inset: a magnified portion of heterostructure (top), a simulated HR-TEM image (middle), and a molecular model (bottom) (Reproduced with permission^[84]. Copyright 2016, Springer Nature).