Collective Electrostatic Engineering of Janus MoSTe nanotubes

One-dimensional (1D) nanotubes of transition metal dichalcogenides (TMDs) exhibit intriguing physical and chemical properties that make them attractive for applications in optoelectronic devices, catalysts, and energy storage. Due to their reduced symmetry and ability to form multiwalled structures, TMD nanotubes show unique electrostatic effects that enable additional routes to tailor their properties, e.g., the band alignment, which is crucial for device performance. In this work, we demonstrate unique electrostatic effects in Janus MoSTe nanotubes using Density Functional Theory (DFT) calculations. By developing an analytical model that quantitatively captures the electrostatic potential, we elucidate the impacts of the diameter, chemical composition, and interface on these effects. Combining two Janus MoSTe nanotubes with different diameters, we observe a pronounced band edge shift of nearly 1.0 eV, which originates from the electrostatic potential within the nanotube pores, leading to a type-II band alignment. The physical insights and analytical framework provide an effective approach for predicting and designing nanotube-based materials with tunable electronic properties for targeted applications.