Extraordinary self-powered Y-shaped flexible film thermoelectric device for wearables

Wearables urgently demand efficient flexible film thermoelectric (TE) technology to self-power the integral electronics. However, limited by the strong correlation between the thickness and temperature gradient across TE legs, film TE devices adopting traditional vertical and lateral pi-shaped configurations are extremely difficult to simultaneously realize excellent flexibility and large power output. In this work, we developed a Y-shaped configuration to solve the dilemma between small thickness and large temperature gradient for TE legs. By using the recently discovered high-performance room-temperature ductile inorganic TE material Ag2Se0.67S0.33, we successfully fabricated extraordinary Y-shaped flexible film TE devices. With the assistance of rational structure design and high-quality Ag2Se0.67S0.33/Pt interface, our devices demonstrate excellent flexibility, large temperature gradient across the TE legs, and record-high output power density among flexible film TE devices in the wearing condition. The generated electricity can drive an electronic watch, showing the great potential for the application in wearable electronics. Herein, by using the ductile thermoelectric material Ag2Se0.67S0.33, we have successfully developed Y-shaped flexible film thermoelectric devices with excellent flexibility and record-high output power density when worn on the human body.