Janus two-dimensional transition metal dichalcogenides

Structural symmetry plays a crucial role in the electronic band structure and properties of two-dimensional materials. In contrast to graphene, monolayer transition metal dichalcogenides exhibit intrinsic in-plane asymmetry with suitable direct bandgaps distinctive optical properties. Efforts have been devoted breaking their out-of-plane mirror by applying external electric fields, vertical stacking, or functionalization. The successful fabrication Janus offers synthetic strategy symmetry, leading variety novel properties, such as piezoelectricity, Rashba spin splitting, excellent exciton Here, we discuss universal approaches unique further present brief perspective on potential applications challenges.