Dramatic Enhancement of Thermoelectric Performance in Two-Dimensional Materials Enabled by Nanoscroll Architecture.

Abstract

Enabling autonomous operation in next-generation nanosystems demands efficient on-chip energy harvesting free from external power. Nanoscale thermoelectric generators are ideal platforms for this goal due to their ambient energy harvesting and scalability. Nevertheless, the thermoelectric performance of the constituent low-dimensional materials is fundamentally limited by the complex coupling of electrical and thermal transport. This work proposes a simple geometric topology strategy that utilizes capillary forces to transform monolayer WS₂ nanoribbons into nanoscrolls, resulting in significantly improved thermoelectric performance. This unique architecture, combining global curvature with local multi-layering, simultaneously activates two synergistic physical mechanisms: (1) the formation of local multi-layer homojunctions significantly narrows the bandgap and reduces thermal activation energy, thereby boosting electrical conductivity by 1-2 orders of magnitude, and (2) curvature-induced inhomogeneous stress fields effectively enhance phonon scattering, leading to a nearly 50% reduction in lattice thermal conductivity. Consequently, such synergistic modulation elevates the figure of merit (ZT) at 273 K to 182 times that of pristine nanoribbons, successfully breaking traditional performance trade-offs. This study validates geometric topology engineering as a generalizable design paradigm for unlocking the potential of two-dimensional nanomaterials, paving the way for high-performance, flexible micro/nano-energy devices.