Inorganic Nanostructures with Strong Chiroptical Activity

Chirality is one of the most remarkable geometrical properties with a variety of manifestations in the material world. The discovery of chirality in inorganic nanostructures spurred the rapid growth of fundamental and applied studies involving chiral nanoscale particles in chemistry, biology, medicine, and physics. While many factors make chiral inorganic nanostructures significant to researchers from many backgrounds, the unique characteristic that drives research in this area is their ability to exhibit high chiroptical activity. In this review, we specifically address its origin in juxtaposition with chiral organic nanostructures. Chiroptical activity depends on multiple factors, including the degree of asymmetry and the size of the object, compared with light wavelength. Nonetheless, it is the high polarizability that distinguishes chiral inorganic matter from what is known from organic chemistry and biology. More importantly, strong light-matter interaction between chiral nanostructures and circularly polarized photons has direct implications for the long-standing fundamental questions about the origin of homochirality on earth and new possibilities for chiral catalysis. Increased insight into chiroptical activity also deepens the existing knowledge about the nanoscale matter and expands its technological applications.