Conjugated polymers promise inherently flexible and low-cost thermoelectrics for powering the Internet of Things from waste heat^1,2. Their valuable applications, however, have been hitherto hindered by the low dimensionless figure of merit (ZT)^3,4,5,6. Here we report high-ZT thermoelectric plastics, which were achieved by creating a polymeric multi-heterojunction with periodic dual-heterojunction features, where each period is composed of two polymers with a sub-ten-nanometre layered heterojunction structure and an interpenetrating bulk-heterojunction interface. This geometry produces significantly enhanced interfacial phonon-like scattering while maintaining efficient charge transport. We observed a significant suppression of thermal conductivity by over 60 per cent and an enhanced power factor when compared with individual polymers, resulting in a ZT of up to 1.28 at 368 kelvin. This polymeric thermoelectric performance surpasses that of commercial thermoelectric materials and existing flexible thermoelectric candidates. Importantly, we demonstrated the compatibility of the polymeric multi-heterojunction structure with solution coating techniques for satisfying the demand for large-area plastic thermoelectrics, which paves the way for polymeric multi-heterojunctions towards cost-effective wearable thermoelectric technologies.

共轭聚合物有望提供本质上灵活且低成本的热电材料，用于利用废热为物联网提供动力 ^1,2 。然而，迄今为止，它们的有价值的应用一直受到低无量纲品质因数 (ZT) ^3,4,5,6 的阻碍。在这里，我们报告了高ZT热电塑料，这是通过创建具有周期性双异质结特征的聚合物多异质结来实现的，其中每个周期由两种具有亚十纳米层状异质结结构和互穿体异质结的聚合物组成界面。这种几何形状显着增强了界面声子类散射，同时保持有效的电荷传输。我们观察到，与单独的聚合物相比，热导率显着降低了 60% 以上，并且功率因数有所提高，导致 ZT 在 368 开尔文时高达 1.28。这种聚合物热电性能超越了商业热电材料和现有的柔性热电候选材料。重要的是，我们证明了聚合物多异质结结构与溶液涂层技术的兼容性，可以满足大面积塑料热电的需求，这为聚合物多异质结迈向具有成本效益的可穿戴热电技术铺平了道路。