2D materials refer to materials that are only one or two atoms thick, such as graphene, phosphorene, and transition metal dichalcogenides. These materials have unique properties due to their ultrathin nature, including high electrical conductivity, flexibility, and transparency. Research in this area focuses on studying the properties of 2D materials, as well as developing new applications in electronics, photonics, and energy storage. Some potential applications of 2D materials include flexible electronics, high-speed transistors, and advanced sensors.