Exploring Two-dimensional Crystals with Atomic Thickness from Molecular Design and Global Structure Search

In the past decade, two-dimensional (2D) materials have attracted intense research interest for their novel properties and great potential in electronics, optoelectronics, and energy applications. The experimental realization of atomic-thickness nanosheets faces a great challenge due to the uncertainty (and long waiting times) in the experiment. Based on first-principle calculations, searching for stable 2D structures with novel physical properties, in theory, has become a rapidly growing field. This chapter summarizes some theoretical predictions of characteristic 2D materials ranging from single elements to their compounds, as well as possible physical properties. It can be inferred that the exploration of 2D materials from molecular design and global search is of great help in accelerating the development of nanoscale materials. Current challenges and prospects of this area are also discussed.