Deviceization of high-performance and flexible Ag₂Se films for electronic skin and servo rotation angle control

Ag₂Se shows significant potential for near-room-temperature thermoelectric applications, but its performance and device design are still evolving. In this work, we design a novel flexible Ag₂Se thin-film-based thermoelectric device with optimized electrode materials and structure, achieving a high output power density of over 65 W m^-2 and a normalized power density up to 3.68 μW cm^-2 K^-2 at a temperature difference of 42 K. By fine-tuning vapor selenization time, we strengthen the (013) orientation and carrier mobility of Ag₂Se films, reducing excessive Ag interstitials and achieving a power factor of over 29 μW cm^-1 K^-2 at 393 K. A protective layer boosts flexibility of the thin film, retaining 90% performance after 1000 bends at 60°. Coupled with p-type Sb₂Te₃ thin films and rational simulations, the device shows rapid human motion response and precise servo motor control, highlighting the potential of high-performance Ag₂Se thin films in advanced applications.