Design Rules for Polymer Blends with High Thermoelectric Performance

Abstract

A combinatorial study of the effect of in‐mixing of various guests on the thermoelectric properties of the host workhorse polymer poly[2,5‐bis(3‐tetradecylthiophen‐2‐yl)thieno[3,2‐b]thiophene] (PBTTT) is presented. Specifically, the composition and thickness for doped films of PBTTT blended with different polymers are varied. Some blends at guest weight fractions around 10–15% exhibit up to a fivefold increase in power factor compared to the reference material, leading to zT values around 0.1. Spectroscopic analysis of the charge‐transfer species, structural characterization using grazing‐incidence wide‐angle X‐ray scattering, differential scanning calorimetry, Raman, and atomic force microscopy, and Monte Carlo simulations are employed to determine that the key to improved performance is for the guest to promote long‐range electrical connectivity and low disorder, together with similar highest occupied molecular orbital levels for both materials in order to ensure electronic connectivity are combined.

Strategic Insights into Semiconducting Polymer Thermoelectrics by Leveraging Molecular Structures and Chemical Doping

“…Zapata-Arteaga et al optimized the PF of F 4 TCNQ-doped PBTTT:P3HT blend polymer films to around 100 μW m −1 K −2 (see Figure 9b−e), which was ∼4 times and over 2 orders of magnitude higher than the PF of neat PBTTT and P3HT films, respectively. 90 It is noticed that, different from the monotonous decrease in σ accompanied with an increase in S in F 4 TCNQ-doped blends of PBTTT:PC 71 BM, the doped PBTTT:P3HT blend films displayed distinct trends of electrical properties with P3HT content. The σ of PBTTT:P3HT blend films generally presented a decreasing trend with the increase of the P3HT fraction, except in the range of 5−15 wt%, which showed an abnormal increasing trend.…”

“…It has to be admitted that, while all of the above studies realized the decoupling of σ and S , the PF of the blended films was still at a relatively low level. Zapata-Arteaga et al optimized the PF of F 4 TCNQ-doped PBTTT:P3HT blend polymer films to around 100 μW m –1 K –2 (see Figure b–e), which was ∼4 times and over 2 orders of magnitude higher than the PF of neat PBTTT and P3HT films, respectively . It is noticed that, different from the monotonous decrease in σ accompanied with an increase in S in F 4 TCNQ-doped blends of PBTTT:PC 71 BM, the doped PBTTT:P3HT blend films displayed distinct trends of electrical properties with P3HT content.…”

“…Thermoelectric properties for films of PBTTT with varied fractions of P3HT and PC 71 BM: (b) σ, (c) S , (d) κ, and (e) PF. Adapted from ref . Copyright 2022 Wiley-VCH.…”

A multifunctional paper-based supercapacitor with excellent temperature adaptability, plasticity, tensile strength, self-healing, and high thermoelectric effects

“…In recent years, the Seebeck effect, which uses ions as carriers, has opened up a new way to develop high-performance thermoelectric devices. [43][44][45][46] However, the currently reported ionic thermoelectric materials are still limited by various factors, and there are some Fig. 7 (a) Self-healing experiment, (b) repeatable self-healing experiment, (c) experiment of self-healing effect on a small bulb, with on and off based on the APC-PVA@ZnCl 2 material.…”

P- and N-dopable ambipolar bulk heterojunction thermoelectrics based on ladder-type conjugated polymers

“…19 Interestingly, the use of p- and n-type conjugated polymer BHJ has not been demonstrated in OTEs, albeit the stimulating work on density of states engineering using pure p- or n-type blends reported by the groups of Katz, Campoy-Quiles and Kemerink. 22–26 Here, we describe for the first time the use of p- and n-type ladder conjugated polymer (PBBTL as p-type and BBL as n-type) blends that can be either p- or n-doped for OTEs (Fig. 1).…”