Mesoscale Chiroptical Order in Achiral Metal-Halide Nanoplatelet Assemblies

This viewpoint presents the circular dichroism emerging directly from the self-assembly of achiral metal-halide perovskite nanoplatelets such as Cs3Cd2Cl7, Rb3Cd2Cl7, and CsPbBr3. Specifically, even when they form only short-range, polydisperse assemblies rather than the long-range helical superlattices reported in prior works, these short assemblies also exhibit chiral optical properties. The effect persists across emissive and nonemissive systems; with diverse stacking morphologies, and both in solution and film forms. Thus, this viewpoint establishes mesoscale chirality as a general principle of nanoplatelet self-assemblies.