Triboelectric‐TFT Flip‐Flop for Bistable Latching of Dielectric Elastomer Actuators

A high‐voltage flip‐flop combining two self‐powered soft sensors with a flexible high‐voltage thin film transistor (HVTFT) is reported, and is used to electrically latch dielectric elastomer actuators (DEAs) in zero and high‐strain states. Two touch‐actuated triboelectric generators (TENGs) provide the gate input for the HVTFT that drives a DEA. One TENG is of positive polarity, while the other is of negative polarity, thus generating voltages either higher (100 V) or lower (−6 V) than the HVTFT threshold voltage. Used in a high‐voltage inverter configuration, there are two stable output voltage states, here 650 V (the “reset” state) and 50 V (the “set” state). The DEA is thus latched in one of two states, at 17.5% and 0% strain. The 650 V output is stable in time, while the 50 V state drifts up to 350 V after 10 s. Due to the highly nonlinear strain–voltage curve of the DEA, the drift of the output voltage in the “set” state leads only to a 2% increase of the DEA actuation strain in 10 s. By enabling bistable control of DEAs with TENGs, the TENG‐HVTFT latch paves the way toward soft robots with flexible embedded control circuitry.