Flexible and Transparent Triboelectric Nanogenerators Based on Polyoxometalate-Modified Polydimethylsiloxane Composite Films for Harvesting Biomechanical Energy

As one of the important friction materials for the construction of high-efficiency triboelectric nanogenerators (TENGs), polydimethylsiloxane (PDMS) has the advantages of high flexibility and transparency. However, the performance of pristine PDMS-based TENGs is not high enough, which limits its practical application. Polyoxometalates (POMs), as a class of nanoscale cluster compounds, have a strong ability to capture electrons. Appropriate POM materials can not only build nanostructures on the surface of PDMS without affecting its flexibility and transparency but also improve its surface roughness and enhance the ability to store charges, thereby enhancing the performance of TENGs. In this study, PDMS is modified by two kinds of Dawson-type POMs, and two POMs-TENGs are further constructed, named W-TENG and MoTENG, respectively. Performance tests show that the Mo-TENG exhibits an output voltage of 30 V and an output current of 500 nA, which are three times and twice that of the pristine PDMS-based TENG, respectively. This enhancement is attributed to POMs dispersed in the PDMS, which increase surface potential, surface roughness, and electronegativity. Finally, the application potential of Mo-TENG in wearable self-powered devices is demonstrated. This study expands the range of applications for POMs and provides an efficient and costeffective method for the commercial manufacture of biosensors and self-powered devices.