Fabrication of Flexible Substrate With Partially Embedded Back Contacts for Piezoelectric ZnO-Based Arms Movement Sensors

The prevailing challenges in developing flexible electronic devices are breaking contacts and perturbed responses during bending operations. This work uses a facile method to fabricate the embedded and firm back contact for flexible electronic devices. The polyvinyl alcohol (PVA) solution in distilled water is employed to synthesize the environment-friendly bendable substrate. The partially embedded back contact using a copper wire was made during the substrate development. For connection and flexibility checks, silver (Ag) and molybdenum disulfide (MoS2) were sputter-coated over the flexible substrate, and different current–voltage (
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) measurements were performed. The results showed excellent contact between the partially embedded copper wire and the deposited thin films. For bending characterization, the
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measurements at different angles (0°–180°) have been carried out for both materials. It revealed the overlapping plots for all angles, suggesting an unperturbed bending response. For practical demonstration, the flexible substrate with partially embedded interdigitated electrodes (IDEs) was fabricated over which a thick film of zinc oxide (ZnO) nanoplates was coated. The
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measurements in flat-bend-flat cycles revealed an enhanced current due to the piezoelectric nature of ZnO in bending states and a full recovery in flat states. Therefore, the as-fabricated device can be considered cost-effective and ready to use as a body-arms movement sensor for medical applications. The developed flexible substrate with embedded contacts facilitating robust electrical connections can also be employed in various electronic devices, such as gas sensors, photodetectors, supercapacitors, and so on.