D. Kos, H. P. A. G. Astier, G. D. Martino, J. Mertens, H. Ohadi, D. De. Fazio, D. Yoon, Z. Zhao, A. Kuhn, A. C. Ferrari, C. J. B. Ford, J. J. Baumberg

Small 14 (2018) 1801599

Nanoactuators are a key component for developing nanomachinery. Here, an electrically driven device yielding actuation stresses exceeding 1 MPa with integrated optical readout is demonstrated. Electrolyte films of 10-nm-thick Al2O3 are sandwiched between graphene and Au electrodes that allow reversible room-temperature solid-state redox producing Al metal and O2 gas in a memristive-type switching device. The resulting high-pressure oxygen microfuel reservoirs are encapsulated under the graphene, swelling to heights of up to 1 μm, which can be dynamically tracked  by plasmonic rulers. Unlike in standard memristors where the memristive redox reaction occurs in single or few conductive filaments, the mechanical deformation forces the constant creation of new filaments over the whole area of the inflated film. The resulting on–off resistance ratios are exceptionally high, reaching 108 in some cycles. The synchronization of nanoactuation and memristive switching in these devices is compatible with large-scale fabrication and has potential for precise and electrically monitored actuation technology.

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