Ultrathin 2D Nonlayered Tellurium Nanosheets: Facile Liquid-Phase Exfoliation, Characterization, and Photoresponse with High Performance and Enhanced Stability

Nonlayered materials are constructed with chemical covalent bonds in all three dimensions, distinct from layered materials, which contain evident structural differences in the horizontal and vertical directions. As a consequence, liquid-phase exfoliation (LPE), a widely explored technique to obtain 2D layered nanoarchitectures, has not yet been fully characterized for the realization of 2D nonlayered nanostructures. Herein, by virtue of a typical chain-like structure of crystalline bulk Te with strong Te-Te covalent bonds in intrachains and weak Van der Waals forces in interchains, ultrathin 2D nonlayered Te nanosheets are realized by means of an LPE method. The resultant 2D Te nanosheets possess a broad lateral dimension ranging from 41.5 to 177.5 nm and a thickness ranging from 5.1 to 6.4 nm, and its photoresponse properties are evaluated using photoelectrochemical measurements. The 2D Te nanosheets exhibit excellent photoresponse behaviors from the UV to the visible regime in association with strong time and cycle stability for the on/off switching behaviors. The fabrication approach of 2D Te nanosheets would arouse interest in exfoliating other nonlayered 2D materials, which would expand the family of 2D materials.