2026-03-09 中国科学院（CAS）
＜関連情報＞
- https://english.cas.cn/newsroom/cas-in-media/202603/t20260309_1152026.shtml
- https://www.science.org/doi/10.1126/science.adx9237
高性能ソフト熱電変換素子のための不規則な階層的多孔質ポリマー Irregular hierarchical-porous polymer for high-performance soft thermoelectrics
Xiao Zhang, Dongyang Wang, Liyao Liu, Zhiyi Li, […] , and Chong-an Di
Science Published:5 Mar 2026
Editor’s summary
The introduction of a hierarchy of pores into a conjugated polymer improves its thermoelectric performance. Zhang et al. created irregularly shaped pores in selenium-substituted diketopyrrolopyrrole by adding polystyrene as a phase-separating agent. After removing the polystyrene, the porous structure showed enhanced phonon-like scattering, which lowered its thermal conductivity, was more crystalline, and had improved charge transport. These films had a thermoelectric figure-of-merit of 1.64 at 343 Kelvin. —Phil Szuromi
Structured Abstract
INTRODUCTION
Conjugated polymers combine low Young’s modulus with excellent solution processability, making them promising candidates for lightweight, low-cost thermoelectric generators in wearable electronics. Nevertheless, their thermoelectric performance remains inferior to that of flexible inorganic materials, and scalable fabrication routes are scarce. To address these limitations, we developed irregular hierarchical-pore thermoelectric polymer (IHP-TEP) films by means of fine-tuned critical-transition phase separation. This approach enables simultaneous modulation of thermal conductivity and charge transport, yielding a substantially enhanced thermoelectric figure-of-merit (zT) for flexible applications.
RATIONALE
High-mobility conjugated polymers typically feature irregular crystalline domains interwoven with amorphous entanglements, generating multiple vibrational modes that facilitate heat flow. Introducing multiscale pores and throats—from <1 nm to a few micrometers—creates diverse phonon-scattering pathways, including boundary scattering, size effects, and phonon-phonon interactions, suppressing lattice thermal conductivity. In parallel, nanoconfinement during phase separation promotes molecular crystallization, improving carrier mobility without sacrificing electrical conductivity. This dual control of heat and charge transport forms the high-performance basis of the IHP-TEP architecture.
RESULTS
To create the IHP-TEP films, we used a critical-transition phase separation method guided by the Flory–Huggins theory. A 70/30 blend of selenium-substituted diketopyrrolopyrrole (PDPPSe-12) with polystyrene produces an interconnected pore network that ranges from 5.9 nm to 1.8 μm (porosity of 0.23 ± 0.01), with narrow throats (5.0 nm to 1.3 μm) packed with fiber-like domains that exhibit strong molecular orientation. Grazing-incidence x-ray scattering reveals π–π stacking contraction from 3.70 to 3.61 Å and crystalline coherence length growth from 38 to 43 Å, signifying improved packing. These IHP-TEP films with confined molecular ordering produce a minimum total thermal conductivity of 0.16 W m−1 K−1 and increase carrier mobility by ≥25%, giving a peak zT of 1.64 at 343 K. The architecture is compatible with scalable spray-coating methods, enabling lightweight, solution-processable thermoelectric generators with normalized power density up to 1.28 μW cm−2 K−2.
CONCLUSION
By integrating randomly distributed, irregular pores and throats across <10 nm to microscale dimensions, IHP-TEP films effectively decouple thermal and electrical transport. The architecture promotes complex heat transport scattering while enhancing charge mobility, enabling record-level zT values in soft thermoelectrics and maintaining solution processability. This broadly applicable design principle can be extended to diverse polymer systems, offering a practical and scalable pathway toward high-performance, flexible, and sustainable thermoelectric generators for wearable and portable energy-harvesting technologies.
Schematic of irregular hierarchical-pore polymer for soft thermoelectrics.
Irregular, multiscale pore engineering in conjugated polymers decouples thermal and electrical transport by suppressing heat flow while boosting charge mobility, achieving a record thermoelectric figure-of-merit zT greater than 1.6 in soft materials. The scalable irregular hierarchical-pore architecture, which is compatible with spray-coating, provides a versatile route to lightweight, flexible generators for next-generation wearable and portable heat-harvesting applications.
Abstract
Polymer thermoelectrics offer an inherently soft, cost-effective, and lightweight solution to convert ubiquitous heat sources into sustainable electricity. However, their realistic applications are hindered by insufficient performance and the scaling complexity. We introduce irregular hierarchical-porous thermoelectric polymers, featuring irregularly shaped and distributed pores with diameters that range from less than 10 nanometers to micrometers. This porous structure not only enhances multiple phonon-like scattering, achieving a 72% reduction in lattice thermal conductivity, but also unexpectedly improves charge transport through nanoconfinement-enhanced crystallization. The optimized film yields a benchmark figure-of-merit zT of 1.64 at 343 kelvin. Moreover, this method is compatible with easy-to-process spray-coating techniques.
