Abstract
The ability to control the movement of charged species in the circuitry of living beings and machines is essential for complex signal processing, computation, and, ultimately, higher functionality. We describe a class of photo-ion generators (PIGs) based on non-ionic photoacids that can create large (> 1000x) irreversible changes in ionic conductivity under illumination, depending on the PIG species, concentration, and solvent. Incorporation of PIGs into elastomers by simple swelling methods yields soft (60 kPa ≤ E ≤ 10 MPa), stretchable, photo-ionic gels (PIGels). The resolution of photo-patterned conductivity in PIGels is less than 1 cm and demonstrates stability over several days, suggesting utility in engineered devices. Leveraging the photo-responsive properties of these materials, we demonstrate high-sensitivity mechanical sensors via conductance changes ([∆G/G0]/σ = 20 MPa-1) and photo-writable, soft circuitry.
Data availability
The data that support the plots within this paper and other findings of this study are available from the corresponding author upon request.
Code availability
The custom code for diffusivity calculation is available from the corresponding author upon request.
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Acknowledgements
The authors acknowledge Tianshu Liu and Tsung-Ching Huang for their support in developing the conductivity characterization experiments.
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T.J.W. conceived the idea of the study. X.L. and S.S. designed the mechanical test setups and fixtures. X.L. and T.J.W. carried out experiments, researched, collected, and analyzed data, and drafted the initial manuscript. S.M.A. and W.P. provided technical support and conceptual advice. T.J.W. supervised the study. All authors discussed the results and commented on the final manuscript.
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Liu, X., Adelmund, S.M., Safaee, S. et al. Soft photo-ionotronics. Nat Commun (2026). https://doi.org/10.1038/s41467-026-69427-8
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DOI: https://doi.org/10.1038/s41467-026-69427-8
