The Polymer Society of Korea

Abstract

Conjugated polymer (CP) is promising thermoelectric (TE) materials due to their broadly tunable electronic structure and mechanical properties. The TE performance of CPs is commonly evaluated by the power factor (PF=σS²), where σ and S denote the electrical conductivity and Seebeck coefficient. However, simultaneous enhancement of σ and S is often hindered by a trade-off resembling the Pisarenko relation, making PF optimization challenging. Here, we blended two CPs with relatively high S and high σ, respectively, to enhance PF. At an optimized blend ratio, σ increases with only a modest reduction in S, resulting in > 100% improvement in PF. To elucidate the underlying mechanism, we correlate electrical characteristics with optical and morphological properties. The results suggest favorable interpolymer interactions yield a complementary microstructure in which the high-σ phase percolates while the high-S phase remains effective, enabling synergistic PF enhancement.