Large-scale production of ultrathin topological insulator bismuth telluride nanosheets by a hydrothermal intercalation and exfoliation route

A convenient hydrothermal intercalation/exfoliation method for large-scale manufacturing of bismuth telluride (Bi2Te3) nanosheets is reported here. Lithium cations can be intercalated between the layers of Bi2Te3 using the reducing power of ethylene glycol in the common hydrothermal process, and high quality Bi2Te3 nanosheets with thickness down to only 3–4 nm are obtained by removing lithium in the following exfoliating process. Scanning electron microscopy, transmission electron microscopy and Raman spectrum characterizations confirm that the high yield of Bi2Te3 nanosheets with good quality were successfully achieved and the sizes of the immense nanosheets reached 200 nm width and 1 μm length. This hydrothermal intercalation/exfoliation method is general, as it has been extended to other layered materials, such as Bi2Se3 and MoS2. Our results suggest a simple route for the large-scale production of thin and flat Bi2Te3 nanosheets, which may be beneficial to further electronic and spintronics applications.