Fig. 2

a SEM images of three types of ZnO NR molds with different heights and pitches: (I) 1.2 μm and 1 μm, (II) 2 μm and 800 nm, (III) 2 μm and 650 nm. b (i)–(iii) The ZNLs on a nanoparticulated TiO₂ film after imprinting using a mold that corresponds to (I)–(III), respectively. The SEM images of the transferred ZNL in a large area are supplied in Additional file 1: Figure S4. All insets show the top view of ZnO NRs in the area of 2.4 × 3.2 μm². All scale bars, 2 μm