Perylenediimide‐Siloxane Block Molecules Displaying Circularly Polarized Emission from Achiral Nanostructured Surfaces

The development of organic dyes is crucial for high‐tech technologies such as displays, telecommunication, and anticounterfeiting. While rylene diimides such as naphthalene and perylene diimides (NDIs and PDIs) exhibit promising optical properties, their crystalline and brittle nature can limit their suitability for flexible or integrated applications. In this work, we display the design and synthesis of both achiral and chiral molecules based on a perylene diimide dye, in conjunction with discrete oligomers of dimethyl siloxane. These molecules phase‐separate into processable, well‐defined columnar nanostructures with sub‐5 nm periodicity. When deposited onto silicon nanorod metasurfaces, both dyes exhibit strongly polarized and directional luminescence ( g lum = 1.09) as a result of the coupling of the emission to optical modes, which are absent without the metasurface. This chiral emission emerges because, at oblique angles of incidence, the metasurface–molecule system becomes extrinsically chiral, no longer being superimposable with its mirror image. These findings demonstrate that highly asymmetric emission can be achieved from intrinsically achiral molecules, which are often synthetically less burdensome compared to their chiral counterparts.