Unravelling the Ageing Effects of PDMS-Based Triboelectric Nanogenerators

Ageing of elastomeric materials in triboelectric nanogenerators (TENGs) often leads to compromised electrical performance and can greatly affect their real-world application as next-generation energy harvesters and self-powered sensors. Herein, the ageing behavior of PDMS-based TENGs is investigated by probing the dielectric and mechanical properties of the membrane materials. Over time, ageing of PDMS after 17 months is evinced by a decline by 71%, 68% and 52% in open-circuit voltage, short-circuit current and charge transfer, respectively, and an increase by 6.8 times in surface charge decay rate. The reduced electrical performance can be attributed to a decrease in work function, dielectric constant, surface adhesion and heterogeneity in stiffness, as well as an increase in loss tangent. The effect of chemical chain scission on the PDMS surface is confirmed through nearfield infrared nanospectroscopy. This study gives insights into the underlying mechanism behind the ageing of PDMS-based TENGs, paving the way to future work for ameliorating these ageing-related issues with the aim to ensure long-term stability of practical triboelectric devices. The effect of ageing on the electrical charge harvesting capacity of polydimethylsiloxane (PDMS)-based triboelectric nanogenerators is interrogated through dielectric and mechanical characterization at micro- and nanoscale resolutions. Nanospectroscopic study reveals the physicochemical mechanism underpinning the evolution of interfacial properties that influence the long-term stability of triboelectric elastomers. image