Mechanisms of Polarity-Driven and Material-Dependent Charge Transfer at PVDF/Polymer Interfaces for High-Performance Triboelectric Nanogenerators

Understanding the microscopic mechanism of interfacial charge transfer is crucial for optimizing the performance of triboelectric nanogenerators (TENGs). Here, a combined first-principles density-functional theory and experimental study reveals how polymer polarity and chemical composition regulate charge transfer at PVDF/polymer interfaces, including Nylon, PDMS, PVC, PE, PTFE, and FEP. The results demonstrate that polar β-PVDF/polymer heterostructures exhibit substantially stronger interfacial charge transfer than nonpolar systems, driven by the intrinsic built-in electric field of β-PVDF. The transferred charges primarily originate from the functional groups of the polymers, and the charge transfer magnitude follows the sequence β-PVDF/Nylon > β-PVDF/PDMS > β-PVDF/PVC > β-PVDF/PE > β-PVDF/PTFE > β-PVDF/FEP, corresponding to electron flow from low work function polymers toward the high work function β-PVDF. Furthermore, these theoretical trends are supported by experimental results, which confirm that β-PVDF-based TENGs deliver higher electrical outputs than α-PVDF-based systems and follow the same material-dependent sequence. This work elucidates the polarization-driven and material-dependent mechanisms of interfacial charge redistribution, providing design principles for high-output and controllable TENGs.