Fig. 3: BNCC of hierarchically organized chiral polycrystals.

a Schematic diagram of biomimetic non-classical crystallization process involving nanocrystal nucleation, aggregation, oriented attachment and mesoscopic transformation. PVP is the amphiphilic polymer to confine Cu-I ionic chains and Cu-I hybrid clusters in the micelle. The Cu₈I₁₂⁴⁻ chains were omitted for clarity. b–e SEM images of different crystallization stages of Cu₄I₄(L₁)₄⁴⁺ Cu₈I₁₂⁴⁻ polycrystals with reaction time of 3 min (b), 20 min (c), 1 h (d), 6 h (e), respectively ([L₁] = 6 mM). f–i SEM images of different crystallization stages of Cu₅I₇(L₃)₂ polycrystals with reaction time of 2 h (f), 4 h (g), 5 h (h), 6 h (i), respectively ([L₃] = 25 mM). j HRTEM image of Cu₄I₄(L₁)₄⁴⁺ Cu₈I₁₂⁴⁻ polycrystals. k Detailed schematic illustration of the driving forces for the chiral regulation of assembly units in the polycrystals. Assembly units are represented by blue rods. The enlarged picture shows the specific steric configuration caused by the interactions between chiral ligands extended out of the (002) planes of the assembly unit surfaces of Cu₄I₄(L₁)₄⁴⁺ Cu₈I₁₂⁴⁻ polycrystals. Interactions between chiral ligands were represented by green shadings.