Black Phosphorus@MXene Heterojunction-Engineered Carbon Nanotube Thermoelectric Films with Synergistic Energy Filtering and Phonon Scattering Effects

Organic thermoelectric (TE) materials incorporating carbon nanotubes (CNTs) attract substantial research interest due to their flexibility, cost-effectiveness, and processability, showing significant promise for wearable TE devices. However, their practical applications are greatly limited by the low Seebeck coefficient ( S ) and high thermal conductivity ( κ ). To overcome these challenges, in this study, black phosphorus@MXene heterojunctions are rationally engineered into CNT matrix, creating TE composite film. This unique “2D heterojunction-3D network” architecture leverages synergistic energy filtering and interfacial phonon scattering to achieve decoupled optimization of electrical conductivity ( σ ), S and κ . Consequently, the composite film attains a high power factor of 521.4 ± 7.7 µW m −1 K −2 at room temperature with a significantly suppressed κ , yielding a figure of merit of 0.0211. These metrics represent a substantial enhancement over pristine CNTs. Furthermore, the film exhibits excellent flexibility and structural stability, contributing to a flexible TE generator prototype with a high power density of 584 µW cm −2 under a temperature gradient of 60 K. This work provides a viable pathway for high-performance, flexible TE materials in self-powered wearable electronics for health monitoring and thermal management.