Light-driven proton transmembrane transport enabled by bio-semiconductor 2D membrane: A general peptide-induced WS2 band shifting strategy.

Light-driven proton directional transport is important in living beings as it could subtly realize the light energy conversion for living uses. In the past years, 2D materials-based nanochannels have shown great potential in active ion transport due to controllable properties, including surface charge distribution, wettability, functionalization, electric structure, and external stimuli responsibility, etc. However, to fuse the inorganic materials into bio-membranes still faces several challenges. Here, we proposed peptide-modified WS 2 nanosheets via cysteine linkers to realize tunable band structure and, hence, enable light-driven proton transmembrane transport. The modification was achieved through the thiol chemistry of the –SH groups in the cysteine linker and the S vacancy on the WS 2 nanosheets. By tuning the amino residues sequences (lysine-rich peptides, denoted as KFC; and aspartate-rich peptides, denoted as DFC), the ζ-potential, surface charge, and band energy of WS 2 nanosheets could be rationally regulated. Janus membranes formed by assembling the peptide-modified WS 2 nanosheets could realize the proton transmembrane transport under visible light irradiation, driven by a built-in potential due to a type II band alignment between the KFC-WS 2 and DFC-WS 2. As a result, the proton would be driven across the formed nanochannels. These results demonstrate a general strategy to build bio-semiconductor materials and provide a new way for embedding inorganic materials into biological systems toward the development of bioelectronic devices. • The designed peptides could be well modified to WS 2 nanosheets through the cysteine linker. • The electronic band structures of the peptide-WS 2 nanosheets were verified through experiments and theoretical calculation. • The assembled bio-semiconductor membrane could realize the light-driven proton transmembrane transport. [ABSTRACT FROM AUTHOR]