Decoupling electron and phonon transport in single-nanowire hybrid materials for high-performance thermoelectrics

Abstract

Organic-inorganic hybrids have recently emerged as a class of high-performing thermoelectric materials that are lightweight and mechanically flexible. However, the fundamental electrical and thermal transport in these materials has remained elusive due to the heterogeneity of bulk, polycrystalline, thin films reported thus far. Here, we systematically investigate a model hybrid comprising a single core/shell nanowire of Te-PEDOT:PSS. We show that as the nanowire diameter is reduced, the electrical conductivity increases and the thermal conductivity decreases, while the Seebeck coefficient remains nearly constant—this collectively results in a figure of merit, ZT, of 0.54 at 400 K. The origin of the decoupling of charge and heat transport lies in the fact that electrical transport occurs through the organic shell, while thermal transport is driven by the inorganic core. This study establishes design principles for high-performing thermoelectrics that leverage the unique interactions occurring at the interfaces of hybrid nanowires.

Unprecedented Multifunctionality in 1D Nb1‐xTaxS3 Transition Metal Trichalcogenide Alloy

“…[ 49 ] The outstanding capacity to carry current observed in Nb 1‐ x Ta x S 3 nanofibers can be attributed to the reduced electron scattering rate due to the crystalline structure of this 1D material. [ 50–52 ]…”

“…[49] The outstanding capacity to carry current observed in Nb 1-x Ta x S 3 nanofibers can be attributed to the reduced elec tron scattering rate due to the crystalline structure of this 1D material. [50][51][52] We also studied the electrical properties of thinfilm Nb 1-x Ta x S 3 on a mica substrate. Figure 3E shows the SEM image of the exfoliated bundle of Nb 1-x Ta x S 3 whiskers.…”

3ω techniques for measurement of volumetric heat capacity and anisotropic thermal conductivity of a solution processable, hybrid organic/inorganic film, Te-PEDOT:PSS

“…Due to the underlying morphology of these films, we expect that the thermal conductivity is higher in the in-plane direction than cross-plane. Single wire measurements of the Te-PEDOT:PSS hybrid have shown that the Te core rather than organic shell is the primary conduit of thermal transport along the wire 19 . In a film of composite material, we expect that interfacial resistances between phases (i.e.…”

Synergistic effect of Zn doping on thermoelectric properties to realize a high figure-of-merit and conversion efficiency in Bi2−xZnxTe3 based thermoelectric generators

“…Some established strategies that decouple these parameters are nanostructuring, doping, band structure modification, defect engineering, energy filtering effect, complex structure formation, etc. [1][2][3][4] Among the state-of-the-art thermoelectric materials, bismuth telluride is broadly used for developing thermoelectric devices near room temperature. [5][6][7][8][9] Although bismuth telluride alloys have been commercialized, devices based on them show saturation in Z (B5-7% in commercial TEGs) due to the inferior zT (B0.9 at 300 K) of the n-type (Bi 2 (Se-Te) 3 ) composition than the zT (B1.35 at 300 K) of the p-type composition ((Bi-Sb) 2 Te 3 ).…”