High Thermoelectric Performance Related to PVDF Ferroelectric Domains in P‐Type Flexible PVDF‐Bi0.5Sb1.5Te3 Composite Film

Abstract

AbstractThere is increasing demand to power Internet of Things devices using ambient energy sources. Flexible, low‐temperature, organic/inorganic thermoelectric devices are a breakthrough next‐generation approach to meet this challenge. However, these systems suffer from poor performance and expensive processing preventing wide application of the technology. In this study, by combining a ferroelectric polymer (Polyvinylidene fluoride (PVDF, β phase)) with p‐type Bi0.5Sb1.5Te3 (BST) a thermoelectric composite film with maximum is produced power factor. Energy filter from ferroelectric‐thermoelectric junction also leads to high Seebeck voltage ≈242 µV K−1. For the first time, compelling evidence is provided that the dipole of a ferroelectric material is helping decouple electron transport related to carrier mobility and the Seebeck coefficient, to provide 5× or more improvement in thermoelectric power factor. The best composition, PVDF/BST film with BST 95 wt.% has a power factor of 712 µW•m−1 K−2. A thermoelectric generator fabricated from a PVDF/BST film demonstrated PmaxT 12.02 µW and Pdensity 40.8 W m−2 under 50 K temperature difference. This development also provides a new insight into a physical technique, applicable to both flexible and non‐flexible thermoelectrics, to obtain comprehensive thermoelectric performance.