Abstract
Biological mechanoreceptors convert tissue strain into distinct spike trains. In contrast, their soft electronic counterparts still rely on discrete components for sensing, preprocessing, and neuronal firing. Here, we integrate these functional components into a single and scalable device by combining mechano-electric transduction and volatile threshold switching within an Ag/freestanding epitaxial SrTiO3/Pt membrane laminated onto a flexible polyethylene naphthalate substrate. Tensile strain (0–2.6%) lowers Ag⁺ migration energy and reduces the switching voltage from 1.04 to 0.24 V. Under constant bias, the spike frequency increases by more than two orders of magnitude, enabling tunable, self-oscillating ‘neurons’ operating below 100 pJ per spike, comparable to biological mechanoreceptors and ~25× more efficient than current flexible sensors. The device maintains its full functionality after over 400 bending cycles, demonstrating its potential as a mechanically programmable, ultralow-power building block for next-generation electronic skins, soft robotics, and bio-integrated prosthetics.
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Acknowledgements
This work was supported by the National R&D Programs (Nos. 2022R1A2C3004135 and RS-2025-02243032) and Nano·Material Technology Development Program (No. 2021M3H4A1A03054864) through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT, and Korea Basic Science Institute (National Research Facilities and Equipment Center) grant funded by the Ministry of Education (No. 2022R1A6C101A754).
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S.K. and C.Y. planned the projects and designed the experiments. S.K. performed the electrical experiments. S.K. and W.R. fabricated the sample. S.K. and J.J. performed atomic force microscopy measurements and XRD measurements, and data analysis. G.O. assisted with the analysis of electrical data. S.K. and B.H.P. supervised the research and interpreted the results, participated in discussions, and wrote the manuscript. All authors discussed the results and commented on the manuscript.
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Kim, S., Yoon, C., Jeon, J. et al. Mechanosensory neuron implemented by a single freestanding epitaxial SrTiO3 capacitor. npj Flex Electron (2026). https://doi.org/10.1038/s41528-025-00520-6
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DOI: https://doi.org/10.1038/s41528-025-00520-6
