Alleviating the trade-off interrelation between seebeck coefficient and electrical conductivity by random copolymerization of two-dimensional and one-dimensional monomers

Abstract

Due to the advantages of good structural tunability, easy processibility, and high mobility, donor-acceptor based polymers are proposed as promising thermoelectric (TE) materials. However, the trade-off phenomenon between Seebeck coefficient (S) and electrical conductivity (σ) severely impedes their TE performance. Although many efforts have been applied to decouple these two parameters, it remains to be a bottleneck. Recently, we found that two-dimensional (2D) BDTTT-based polymers displayed high S with moderate σ. Combining one-dimensional (1D) conjugated structure (DPP-EDOT) with 2D conjugated structure (BDTTT-DPP) by random copolymerization can endow the polymers with good S and σ, thus alleviating the conflict. Among the polymers, P(BDTTT-DPP)1:P(DPP-EDOT)2 (P12) displayed the best power factor of 12.30 μW m−1 K−2 at room temperature, which is 4 and 1.3 times higher than that of P(BDTTT-DPP) (P10) and P(DPP-EDOT) (P01), respectively. These results provide an attractive guidance for fabricating the TE polymers with high performance by random copolymerization of two-dimensional and one-dimensional monomers.