The rapid development of flexible electronics has attracted a growing interest in flexible thermoelectric materials. Against this background, the development of ternary organic-inorganic composites represents a promising route for improving the thermoelectric (TE) performance and flexibility of materials, especially in systems incorporating one-dimensional (1D) whiskers. Ta4SiTe4, a recently identified 1D material, displays exceptional electronic transport properties. However, its composite with insulating poly(vinylidene fluoride) (PVDF) suffers from limited carrier transport. In this study, fluorinated copper phthalocyanines (FxCuPc) are introduced to fabricate n-type Ta4SiTe4/FxCuPc/PVDF ternary composite films. Characterizations confirm the formation of the FxCuPc-Ta4SiTe4 nanointerface. With increasing fluorine substitution, the energy levels of FxCuPc shift downward and F16CuPc exhibits a conduction band edge slightly lower than that of Ta4SiTe4, enabling efficient electron transfer at the interface and serving as an effective charge transport bridge between adjacent whiskers. This interfacial design simultaneously enhances the electrical conductivity by lowering the contact barrier and increases the Seebeck coefficient through mild carrier concentration modulation and energy-filtering effects. The optimized 50 wt % Ta4SiTe4/F16CuPc/PVDF composite film exhibits a 50% enhancement in electrical conductivity over the binary 50 wt % Ta4SiTe4/PVDF film, together with a moderate increase in the Seebeck coefficient. Consequently, a maximum power factor of 385.9 μW m-1 K-2 is achieved at 5% F16CuPc loading, representing a nearly 50% enhancement compared to the binary 50 wt % Ta4SiTe4/PVDF composite (255.6 μW m-1 K-2). This work demonstrates an effective molecular design strategy for optimizing carrier transport in organic-inorganic hybrid films toward high-performance flexible thermoelectric applications.
Liu et al. (Wed,) studied this question.