ScholarWorks@성균관대학교

초록

Thermoelectric generators (TEGs) offer a solid-state platform for converting low-grade waste heat into electricity, yet their efficiency remains fundamentally constrained by low figures of merit (ZT) and limited interfacial transport. Here, we report a ferroelectric field-gating strategy enabled by integrating poled ferroelectric ceramics Pb(Ni1/3Nb2/3)O3–Pb(ZrxTi1-x)O3 (PNN–PZT) at the cold junction of BiSbTe-based TEGs. The remanent polarization of the ferroelectric layer generates a built-in electrostatic field that biases carrier transport at the device level while preserving the intrinsic conduction pathway of the thermoelectric material. As a result, the output voltage and power are enhanced by factors of about 2.2 and 4, respectively, under a temperature gradient of 25 K, with only slight changes in intrinsic thermoelectric properties. Compositional tuning via BaTiO3 incorporation reveals a clear correlation between remanent polarization and output enhancement, supporting a polarization-dependent gating mechanism. Coupled electro-thermal finite element simulations further confirm the role of polarization-induced electrostatic fields in modulating carrier transport under an applied thermal gradient. The enhanced electrical output remains stable over 5 weeks. When applied to thermoelectric cooling systems, the ferroelectric integration accelerates the transient cooling response by approximately twofold, while the steady-state cooling temperature remains unchanged. By introducing a stable, humidity-resistant electrostatic bias outside the thermoelectric current path, this work demonstrates a scalable device-level strategy for improving voltage output and thermal response with only slight changes in intrinsic ZT, offering practical advantages for low-grade heat recovery and self-powered thermal management applications.

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