Flexible Carbon Nanotube‐Epitaxially Grown Nanocrystals for Micro‐Thermoelectric Modules

Abstract Flexible thermoelectric materials have attracted increasing interest because of their potential use in thermal energy harvesting and high‐spatial‐resolution thermal management. However, a high‐performance flexible micro‐thermoelectric device (TED) compatible with the microelectronics fabrication process has not yet been developed. Here a universal epitaxial growth strategy is reported guided by 1D van der Waals‐coupling, to fabricate freestanding and flexible hybrids comprised of single‐wall carbon nanotubes and ordered (Bi,Sb) 2 Te 3 nanocrystals. High power factors ranging from ≈1680 to ≈1020 µW m −1 K −2 in the temperature range of 300–480 K, combined with a low thermal conductivity yield a high average figure of merit of ≈0.81. The fabricated flexible micro‐TED module consisting of two p–n couples of freestanding thermoelectric hybrids has an unprecedented open circuit voltage of ≈22.7 mV and a power density of ≈0.36 W cm −2 under ≈30 K temperature difference, and a net cooling temperature of ≈22.4 K and a heat absorption density of ≈92.5 W cm −2 .