Antioxidative 2D Bismuth Selenide via Halide Passivation for Enhanced Device Stability.

The topological insulator 2D BiSe is promising for electronic devices due to its unique electronic properties; however, it is challenging to prepare antioxidative nanosheets since BiSe is prone to oxidation. Surface passivation using ligand agents after BiSe exfoliation works well to protect the surface, but the process is time-consuming and technically challenging; a passivation agent that is stable under a highly biased potential is significant for in situ passivation of the BiSe surface. In this work, the roles of halide anions (Cl, Br, and I) in respect of the chemical properties of synthetic BiSe nanosheets during electrochemical intercalated exfoliation were investigated to determine the antioxidation capacity. It was found that BiSe nanosheets prepared in a solution of tetrabutylammonium chloride (TBA and Cl) have the best oxidation resistance via the surface bonding of Bi with Cl, which promotes obtaining better device stability. This work paves an avenue for adjusting the components of the electrolyte to further promote the stability of 2D BiSe-nanosheet-based electronic devices.