Understanding Diameter and Length Effects in a Solution‐Processable Tellurium‐Poly(3,4‐Ethylenedioxythiophene) Polystyrene Sulfonate Hybrid Thermoelectric Nanowire Mesh

Madeleine P Gordon,Kyle Haas,Akanksha K Menon,Edmond Zaia,Ayaskanta Sahu,Lin Yang,Alexandra Bruefach,Michael D Galluzzo,Jeffrey J Urban,Mary C Scott,Ravi S Prasher

doi:10.1002/aelm.202000904

Abstract

AbstractOrganic–inorganic hybrids offer great promise as solution‐processable thermoelectric materials. However, they have struggled to surpass the performance of their rigid inorganic counterparts due, in part, to a lack of synthetic control and limited understanding of how inorganic nanostructure dimensions impact overall charge transport. While it has been hypothesized that length, diameter, and aspect ratio (AR) all impact electronic transport in hybrid nanowires, the field lacks clarity on the relative role of each. In this study, the experimental parameter of ligand molecular weight (MW) is investigated as a synthetic knob for modulating nanowire dimensions, as well as the deconvolution of nanowire length versus diameter impacts on electron transport. By increasing ligand MW, larger nanowire AR dispersions occur and an optimal power factor of ≈130 μWm−1 K−2 is achieved for a modest AR of 73. Power factors of this magnitude are thought to only be achievable in ultrahigh AR systems; representing a 183% increase in performance over literature reports with similar AR. Additionally, nanowire diameter is demonstrated to be a far more sensitive parameter for enhancing performance than modulating length. This study provides improved fundamental insight into rational synthetic design avenues for future enhancements in the performance of hybrid materials.

Highlights

Organic–inorganic hybrids offer great promise as solution-processable thermoelectric materials
By increasing ligand molecular weight (MW), larger nanowire aspect ratio (AR) dispersions occur and an optimal power factor of ≈130 μWm−1 K−2 is achieved for a modest AR of 73
Www.advelectronicmat.de find that increased PVP MW results in larger NW AR dispersions where NW length remains relatively constant but diameter decreases, and an optimal power factor of 130 μW mK−2 is achieved at a modest AR of 73

Summary

Understanding Diameter and Length Effects in a SolutionProcessable Tellurium-Poly(3,4-Ethylenedioxythiophene) Polystyrene Sulfonate Hybrid Thermoelectric Nanowire Mesh. A. Sahu Department of Chemical and Biomolecular Engineering New York University Brooklyn, NY 11201, USA www.advelectronicmat.de find that increased PVP MW results in larger NW AR dispersions where NW length remains relatively constant but diameter decreases, and an optimal power factor of 130 μW mK−2 is achieved at a modest AR of 73. Sahu Department of Chemical and Biomolecular Engineering New York University Brooklyn, NY 11201, USA www.advelectronicmat.de find that increased PVP MW results in larger NW AR dispersions where NW length remains relatively constant but diameter decreases, and an optimal power factor of 130 μW mK−2 is achieved at a modest AR of 73 Such high performance is in contrast with previous reports of the same hybrid material synthesized via different means, wherein an ultrahigh AR of ≈1000 was required for a comparable power factor. This in turn will guide the rational design of generation high performing hybrid materials in order to realize their potential in devices for a wide array of energy harvesting applications

Experimental Section

Findings

Conflict of Interest