Fig. 4.

Structure and optical characteristic of C/S-NWs. a Optical image and corresponding FM images under excitation by b the UV band and c green-light of an individual DB-C/S-NW with scale bar of 5 μm. d Spatially resolved PL spectra and e PL decay curves collected from different locations marked in (b). Inset of d: corresponding polar image of the peak intensities. f The SEM image of a typical DB-C/S-NW and the corresponding EDS mapping for g Br and h I; scale bar: 5 μm. The element I and Br distribution along i vertically and j parallel directions marked in d₁. FM images of DB-C/S-NWs based on different ratio between the halogen bond acceptor of F₄DIB and the hydrogen bond acceptor of BrFTA: k, n 1:1, l, o 1:2 and m, p 1:3; scale bar: 20 μm. The excitation source for (k–m) and (n–p) are the UV light and green-light, respectively