MICROPYRAMID STRUCTURED PHOTO CAPACITIVE INTERFACES
Vedran Đerek1*, Marta Nikić1, Aleksandar Opančar1, Florian Hartmann2,3, Ludovico Migliaccio4, Marie Jakešová4 and Eric Daniel Głowacki4*
1Department of Physics, Faculty of Science, University of Zagreb, Bijenička c. 32, 10000, Zagreb, Croatia; 2Soft Matter Physics, Institute of Experimental Physics, Johannes Kepler University Linz, Altenberger Strasse 69, Linz, 4040 Austria; 3Soft Materials Lab, Linz Institute of Technology LIT, Johannes Kepler University, Altenberger Strasse 69, Linz, 4040 Austria; 4Central European Institute of Technology, Brno University of Technology, Purkyňova 123, 61200 Brno, Czech Republic
Optically driven extracellular electronic neuromodulation devices are a novel tool in basic research and offer new prospects in medical therapeutic applications. Optimal operation of such devices requires efficient light capture and charge generation, effective electrical communication across the device’s bioelectronic interface, conformal adhesion to the target tissue, and mechanical stability of the device during the lifetime of the implant – all of which can be tuned by spatial structuring of the device. We demonstrate an 3D structured opto-bioelectronic device – an organic electrolytic photocapacitor spatially structured by depositing the active device layers on an inverted micropyramid-structured substrate. Ultrathin, transparent, and flexible micropyramid-structured foil was fabricated by chemical vapor deposition of parylene C on silicon molds containing arrays of inverted micro pyramids, followed by a peel-off procedure. The capacitive current delivered by the devices showed a strong dependency on the device structuring. The device performance was evaluated by numerical modelling, enabling functional optimization of the devices for specific purposes. Additionally, micropyramid structuring is expected to affect the device-tissue adhesion and afford a level of stretchability to otherwise flexible but non-stretchable parylene C foil substrates.
Acknowledgements: This work has been supported by the Croatian Science Foundation under the project 3Doptobio UIP-2019-04-1753 and the project CeNIKS, co-financed by the Croatian Government and the European Union through the European Regional Development Fund – Competitiveness and Cohesion Operational Programme (grant no. KK.01.1.1.02.0013), and the QuantiXLie Center of Excellence, a project co-financed by the Croatian Government and European Union through the European Regional Development Fund – the Competitiveness and Cohesion Operational Programme (grant no. KK.01.1.1.01.0004). Financial support by the Center of Excellence for Advanced Materials and Sensors, Croatia, is gratefully acknowledged.
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