Interlayer Mobility Control of 2D-Layered Crystals for Delamination of Nanosheets

Abstract

To maintain consistent properties of delaminated two-dimensional nanosheets, mild methods to preserve large lateral sizes and crystallinity during the delamination of bulk crystals are desired. This study introduces a gentle, solution-based on-substrate delamination strategy that avoids forming colloidal free-standing nanosheets by postponing the delamination process until the materials are deposited on the substrate, thereby preventing physical fragmentation in solution. By comparing cone-type and cylinder-type molecular intercalates (oleylamine and hexadecylamine), we identify interlayer mobility as a governing parameter for delamination in intercalation-accessible layered crystals, eliminating the need for external energy input such as sonication. Operando microscopic analyses reveal the importance of the gas–liquid interface during the evaporation process of drop-cast samples, which induces shear forces necessary for delamination. Application to a range of layered oxides and chalcogenides (HNb3O8, HTaMoO6, HTiNbO5, MoO3, V2O5, and TiS2) illustrates the transferability of this working principle across chemically distinct layered materials sharing sufficient interlayer adaptability. These proof-of-concept findings demonstrate that controlling interlayer mobility through molecular engineering provides an alternative route to producing large-area, high-quality 2D nanosheets.