Solution Synthesis of Layered van der Waals (vdW) Ferromagnetic CrGeTe Nanosheets from a Non-vdW CrTeTemplate.

CrGeTe has recently emerged as a new class of two-dimensional (2D) materials due to its intrinsic long-range ferromagnetic order. However, almost all the reported synthesis methods for CrGeTe nanosheets are based on the conventional mechanical exfoliation from single-crystalline CrGeTe, which is prepared by the complicated self-flux technique. Here we report a solution-processed synthesis of CrGeTe nanosheets from a non-van der Waals (vdW) CrTe template. This structure evolution from non-vdW to vdW is originated from the substitution of Ge atoms on the Cr sites surrounded by fewer Te atoms in the CrTe lattice due to their smaller steric hindrance and lower energy barrier. These CrGeTe nanosheets present regular hexagonal structures with a diameter larger than 1 μm and excellent stability. They exhibit soft magnetic behavior with a Curie temperature lower than 67.5 K. This non-vdW to vdW synthesis strategy promotes the development of CrGeTe in ferromagnetism while providing an effective route to synthesize other 2D materials.