Fig. 5: Deterministic twisted angle via interlayer interaction engineering.
From: Moiré two-dimensional covalent organic framework superlattices
a, Calculated system energy variation as a function of the twisted angle between top and bottom COF layers normalized by pyrene unit. b, Electrostatic potential surface (Ha) for 27-(top) and 16-(bottom) PDBA periodic monolayers projected on the 0.05 eÅ−3 electron density isosurface. c, Large-scale STM image revealing the moiré superlattice formed by twisted bilayer 2D-COFs. d, FFT of c. The hexagonal arranged white circle points out the COFs-2 lattice, while the inner yellow hexagon indicates the superlattice. e, High-resolution STM image of the structure shown in c. Imaging conditions: 150 nm × 150 nm, Vs = 0.2 V, It = 0.12 nA (c); 40 nm × 40 nm, Vs = 0.2 V, It = 0.18 nA (e).
