Emerging chiral two-dimensional materials.

Research into 2D materials has been growing with impressive speed since the discovery of graphene. Such layered materials with ultrathin morphologies and extreme aspect ratios currently display a vast range of properties; however, until recently a conspicuously missing property of 2D materials was global chirality. The situation has changed over the past few years with the implementation of several distinct types of ultrathin chiral 2D crystals. Here we offer a forward-looking perspective on this field to comprehend the fundamentals of global chirality in two dimensions and develop new directions. We specifically discuss the experimental achievements of the emerging chiral 2D materials with a focus on their design strategy, synthesis, structural characterization, fundamental physical properties and possible applications. We will highlight how the molecular-scale local chirality could be significantly transmitted and amplified throughout ultrathin single-crystalline 2D structures, resulting in distinctive global chirality that brings more sophisticated functions.