Interface Engineering via Sb ₂ Te ₃ Deposition Enables High‐Performance SWCNT Film Thermoelectrics

ABSTRACT Single‐walled carbon nanotubes (SWCNTs) possess attractive features including low cost, non‐toxicity, high flexibility, and excellent electrical conductivity, making them promising candidates for thermoelectric applications. However, their thermoelectric performance remains insufficient to meet practical requirements. In this study, we propose an effective strategy to fabricate high‐performance thermoelectric composite films by depositing Sb ₂ Te ₃ onto a flexible SWCNT substrate. The resulting composite film exhibits a room‐temperature power factor of 25.82 µW cm ⁻¹ K ⁻² , among the highest values reported for SWCNT‐based films. First, the SWCNT film is densified via a cold‐pressing process, significantly enhancing its electrical conductivity without degrading the Seebeck coefficient. Subsequently, Sb ₂ Te ₃ is deposited onto the SWCNT surface to construct engineered interfaces. These interfaces promote energy filtering and facilitate charge transport between SWCNTs and Sb ₂ Te ₃ , leading to simultaneous enhancement of the Seebeck coefficient and power factor. Both simulation and experimental results confirm the effectiveness of this approach. A six‐legged device fabricated from the composite film delivers a maximum output power density of approximately 3 mW cm ⁻² under a temperature difference of 40 K, while maintaining excellent flexibility and mechanical adaptability. This study presents a scalable and effective strategy for integrating SWCNT‐based materials with inorganic thermoelectrics, offering strong potential for flexible energy harvesting applications.