Pentagonal 2D Transition Metal Dichalcogenides: PdSe2 and Beyond

Abstract 2D materials with common hexagonal crystal structures, such as graphene, hexagonal boron nitride, and transition metal dichalcogenides have attracted great interest due to their novel physical and chemical properties. Pentagonal transition metal dichalcogenides (TMDs) exhibit distinct optical, electrical, and chemical properties, with valuable functionalities for various applications. This review highlights some of the most important developments in this field, with emphasis on their functionalities for neuromorphic computing, transistors, photodetection, catalysts, etc. Strategies for modifying their physical and chemical properties as well as device performance including defect engineering and interface engineering are presented. Finally, a forward‐looking outlook of pentagonal 2D materials is discussed.