Temperature-tuned enhanced performances of PVDF-based flexible triboelectric nanogenerator

A ferroelectric PVDF-based flexible triboelectric nanogenerator (TENG) has been fabricated to analyze the effect of ambient temperature on the electrical outputs. The open-circuit voltage increased from 6.2 to 20 V with the increase in the ambient temperature up to 41 °C. However, beyond 41 °C, the electrical outputs start decreasing. Through tuning the ambient temperature, an ∼11-fold enhancement in the output power density of the TENG was achieved. In order to investigate the mechanism behind the temperature-tuned TENG outputs, the temperature-dependent dielectric permittivity and conductivity of the film have been studied. The dielectric permittivity and conductivity of the films are observed to increase with the temperature. The increase in the dielectric permittivity has been attributed to the PVDF segmental chains' movements, causing the enhancement in dielectric permittivity, which results in more surface charge and improvements in the TENG electrical outputs. However, a large increment in film conductivity at higher temperatures causes the leakage of surface charges, resulting in a decrement in TENG outputs. Furthermore, the temperature-dependent performance of PVDF-CdS nanocomposite-based TENG has also been investigated and found to enhance the performance from 8 to 27 V with the increase in temperature from 33 to 41 °C. The additional interfacial polarization between CdS nanoparticles and the PVDF matrix and higher ferroelectricity in nanocomposites contribute to larger TENG outputs of the PVDF/CdS nanocomposite-based TENG device.