Selenium‐Substituted Diketopyrrolopyrrole Polymer for High‐Performance p‐Type Organic Thermoelectric Materials

Development of high‐performance organic thermoelectric (TE) materials is of vital importance for flexible power generation and solid‐cooling applications. Demonstrated here is the significant enhancement in TE performance of selenium‐substituted diketopyrrolopyrrole (DPP) derivatives. Along with strong intermolecular interactions and high Hall mobilities of 1.0–2.3 cm² V^?1 s^?1 in doping‐states for polymers, PDPPSe‐12 exhibits a maximum power factor and ZT of up to 364 μW m^?1 K^?2 and 0.25, respectively. The performance is more than twice that of the sulfur‐based DPP derivative and represents the highest value for p‐type organic thermoelectric materials based on high‐mobility polymers. These results reveal that selenium substitution can serve as a powerful strategy towards rationally designed thermoelectric polymers with state‐of‐the‐art performances.