Enhanced n-Type Thermoelectric Behavior of Polydopamine-Based Composites

Dehydrated polyvinyl alcohol (cPVA) was used as novel oxygen-containing carbon material fillers to prepare a series of [Formula: see text]-type polydopamine (PDA)-based PDA/cPVA (PP) composites. The long [Formula: see text]-conjugated surface with C[Formula: see text]C and C[Formula: see text]O structures of cPVA provided binding sites for PDA to form an effective conductive network. PP samples were further pyrolyzed at 800[Formula: see text]C to get cPP composites, in which N, O-doped graphite-like structure was obtained and their [Formula: see text]-type thermoelectrical performance was significantly enhanced. Structural results revealed that the combination of cPDA and cPVA benefited the graphitization process of cPP when the mass ratios of dopamine monomer to cPVA were 1:0.1 (cPP0.1). Besides, the shortened interplanar distance between cPDA and cPVA facilitated carrier transport and hence benefited the electrical conductivity of cPP0.1 composites. The energy filtering effects due to energy level mismatch caused a significant enhancement of the Seebeck coefficient (−85.3[Formula: see text][Formula: see text]V K[Formula: see text] when cPP0.1 composites were pyrolyzed at 800[Formula: see text]C, which was much higher than that of pure cPDA (−54.9[Formula: see text][Formula: see text]V K[Formula: see text]. This work provides a simple and effective method to obtain TE materials with enhanced [Formula: see text]-type performance.