Autonomous MXene-PVDF actuator for flexible solar trackers

We report a novel flexible solar tracking system based on a photothermal-thermomechanical (PT-TM) actuator comprised of Ti3C2Tx MXene and polyvinylidene fluoride (PVDF) bilayer. The actuation function of the proposed device originates from photothermal and surface plasmon-assisted effects in MXenes, coupled with thermomechanical deformation of in-plane aligned PVDF polymer. Two types of solar tracking modes are evaluated based on the experimental deformation behavior of the PT-TM actuator. We find that the uniaxial East-West solar tracking option increases the overall energy intensity reaching the solar module by over 30%, in comparison with the optimized tilting-controlled mode. We also demonstrate the thermally driven self-oscillation of the MXene-PVDF device, which may have promising potential for optically and thermally driven soft robotics. The PT-TM actuator devices display robust mechanical strength and durability, with no noticeable degradation in their performance after more than 1000 cycles. A novel flexible photothermal-thermomechanical (PT-TM) actuator comprised of Ti3C2Tx MXene and polyvinylidene fluoride (PVDF) bilayer is developed. The actuation function of the proposed device originates from photothermal and surface plasmon-assisted absorption in MXenes, coupled with thermomechanical deformation of in-plane aligned PVDF polymer. The actuator can greatly enhance solar energy harvesting compared to a tilt-controlled solar tracking system. [Display omitted] •The actuation mechanism is shown to originate from thermomechanical deformation of the in-plane aligned PVDF polymer chains coupled with optical absorption effects in MXene.•We demonstrate that our autonomous actuator can be used in a solar tracking application and can increase the overall energy intensity reaching the solar module by over 30% compared to the optimized tilting-controlled mode.•We also demonstrate thermally driven self-oscillation of MXene-PVDF device, which may have potential in optically and thermally driven soft robotics.