Blended Conjugated Host and Unconjugated Dopant Polymers Towards N‐type All‐Polymer Conductors and High‐ZT Thermoelectrics

N-Type thermoelectrics typically consist of small molecule dopant+polymer host. Only a few polymer dopant+polymer host systems have been reported, and these have lower thermoelectric parameters. N-type polymers with high crystallinity and order are generally used for high-conductivity ( σ σ ) organic conductors. Few n-type polymers with only short-range lamellar stacking for high-conductivity materials have been reported. Here, we describe an n-type short-range lamellar-stacked all-polymer thermoelectric system with highest σ σ of 78 S⁻¹ , power factor (PF) of 163 μW m⁻¹ K⁻² , and maximum Figure of merit (ZT) of 0.53 at room temperature with a dopant/host ratio of 75 wt%. The minor effect of polymer dopant on the molecular arrangement of conjugated polymer PDPIN at high ratios, high doping capability, high Seebeck coefficient (S) absolute values relative to σ σ , and atypical decreased thermal conductivity ( κ κ ) with increased doping ratio contribute to the promising performance.