Two-Dimensional Nanomaterials with Unconventional Phases

Abstract

Two-dimensional (2D) nanomaterials have attracted increasing interest because of their compelling physicochemical properties and promising applications. Recent studies have demonstrated that phases of nanomaterials could significantly affect their properties and applications because of the distinct atomic arrangements. Besides crystalline phases, the amorphous nanomaterials, which lack long-range atomic ordering, and heterophase nanostructures consisting of more than one phase have also shown enhanced performances in some specific applications. Recently, with the rapid development in phase engineering of nanomaterials (PEN), the controlled synthesis of 2D nanomaterials with unconventional phases and the exploration of phase-dependent properties and applications have been witnessed. In this perspective, we briefly summarize the research progress on 2D nanomaterials with unconventional phases, including unconventional crystal phases, amorphous phase, and heterophase. On the basis of different material categories, we highlight their synthetic methodologies, unique structures, and intriguing properties. Finally, we provide personal insights on challenges and potential research opportunities in this emerging field.

Metallic 1T Phase Enabling MoS2 Nanodots as an Efficient Agent for Photoacoustic Imaging Guided Photothermal Therapy in the Near‐Infrared‐II Window

“…Phase engineering of nanomaterials has been one of the hottest research topics in recent years since the crystal phase has been proven to be one of the key factors to affect the properties and application performance of nanomaterials owing to their distinctive atomic arrangements and/or coordination modes. [16][17][18] As a representative class of materials, transition metal dichalcogenides (TMDs) have been intensively explored in the field of phase engineering of nanomaterials since they can crystallize into different crystal phases, including 2H, 1T, 1T′, and 3R phases. [19] Importantly, TMDs with different phases could exhibit distinctively different properties.…”

High‐Yield Exfoliation of Ultrathin 2D Ni3Cr2P2S9 and Ni3Cr2P2Se9 Nanosheets

“…Layered 2D metal chalcogenide nanomaterials, especially transition metal dichalcogenides (TMDs), have been extensively studied in last decade owing to their intriguing physicochemical properties as well as numerous promising applications. [ 1–9 ] Recent studies have revealed that introducing a third element into binary layered 2D metal chalcogenides allows the preparation of ternary layered 2D nanomaterials, such as metal chalcogenides (e.g., Ta 2 NiS 5 and Cu 2 WS 4 ) [ 10–13 ] and metal phosphorus trichalcogenides (MPS 3 : M = Mn, Fe, Ni, Zn, etc.). [ 14–19 ] These ternary layered 2D nanomaterials normally exhibit distinct physicochemical properties and innovative applications as compared to binary 2D metal chalcogenide nanomaterials due to their unique crystal structures and versatile compositions.…”

Quasi‐Epitaxial Growth of Magnetic Nanostructures on 4H‐Au Nanoribbons

“…Phase engineering of nanomaterials (PEN) [ 1 ] is attracting increasing research interest, since the crystal phases of metallic nanomaterials play an important role in determining their physicochemical properties, such as magnetic, optical, electrical, and catalytic properties. [ 2–4 ] For example, Co nanomaterials with hexagonal‐close‐packed (hcp), face‐centered‐cubic (fcc), and ε phases exhibit different magnetic properties. The hcp‐Co nanomaterials are hard magnetic materials, whereas those in fcc and ε phases are soft magnetic materials.…”