Simulation-aided studies on the superior thermoelectric performance of printable PBDTT-FTTE/SWCNT composites

Quasi one-dimensional (1D) carbon nanostructures hybridized with p-conjugated polymeric systems are vastly explored for their unique heat/carrier transport beneficial for thermoelectric (TE) applications. We present the TE response of all-organic composites fabricated with poly[4,8-bis(5-(2-ethylyhexyl)thio-phene-2-yl)benzo[1,2-b; 4,5-b']dithiophene-2,6-diyl-alt-(4-(2-ethylhexyl)3-fiuorothieno[3,4-b']thio-phene-)-2-carboxylate-2-6-diyl)] (PBDTT-FTTE) and single-walled carbon nanotube (SWCNT). SWCNTs form strong pi-pi interfacial interactions with the polymer, and their TE performance is improved through p-doping with ferric chloride (FeCl3). Investigation of the electrical conductivity (u) and Seebeck coef-ficient (alpha) reveals a characteristic mechanism arising from low-energy carrier filtering and Fermi-level pinning. DIGIMAT-MF (c) material modeling platform simulates sigma and thermal conductivity (k) and in-dicates a CNT aspect ratio distribution in the system. The doped composite with 55 wt% SWCNT exhibits the maximum ZT value of 0.044 at 303 K using the simulated k value. A fiexible TE generator (TEG) consisting of 21 legs is dispenser printed that produces similar to 32.7 nW power output with a 65 K temperature gradient across 15 kU load resistance. COMSOL Multiphysics (R) simulation is used to optimize TEG design for maximum extractable output power. (c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

The thermolectric properties of all-organic composites fabricated with a polymeric system and single-walled carbon nanotubes (SWCNTs) were investigated. It was found that SWCNTs, when hybridized with the polymer, exhibited improved thermoelectric performance, which was further enhanced through p-doping with ferric chloride.