SEM (a), FESEM ((b)–(e)), TEM (f), and AFM ((g)-(h)) micrographs and data of ONRs coated with coordination ST-NPs 2. (a) A bunch of ONRs coated with ST-NPs; (b) close-ended feature of a ONR; ((c), (d)) a nanorod clearly shows the presence of spherical ST-NP aggregates on it; (e) energy dispersive X-ray analysis (EDAX) data collected on ST-NPs coated on ONR; (f) the dark (ST-NPs) and grey colour (ONR) contrast clearly distinguish the NPs from the ONRs; (g) AFM image of a single ONR coated with ST-NPs. (h) Cross-section profile along the red line in (g). Scale bars are: (a) 10 m; (b), (c): 2 m; (d) 1 m; and (f) 200 nm.