Design and Batch Fabrication of Stretchable Bifunctional Sensor Using Polyaniline and ZnO Nanostructures for Tensile and UV Sensing

The rapid advancement of wearable devices has increased interest in electronic skin (
$e$
-skin) equipped multifunctional sensors. Consequently, research is underway to develop stretchable sensors capable of detecting multiple external stimuli. These sensors often employ various 1-D nanomaterials to enhance their sensing performance. This article introduces a novel structure and batch fabrication process for a stretchable bifunctional sensor. This sensor is composed of polyaniline nanofibers (PANI NFs) and zinc oxide nanorods (ZnO NRs), arranged in polydimethylsiloxane (PDMS). We used three Au electrodes to help measure the electrical properties of the detectors. The substrate of the stretchable bifunctional sensor was crafted from a single substrate, which comprises two types of PDMS. This design aims to achieve a Young modulus similar to human skin while protecting the Au electrodes and ZnO NRs from deformation. We also introduce a novel batch fabrication process that sequentially synthesizes PANI NFs and ZnO NRs. Unlike previous studies that used stacked structures or nanorod composites, our approach allows these nanomaterials to retain their individual sensor properties, thereby ensuring enhanced conductivity and sensitivity. As a result, the PANI NFs showed clear and repeatable sensing properties and high strain sensitivity with gauge factors exceeding 63 under 30% strain. In addition, the external quantum efficiency (EQE) of ZnO NRs reached 79.6% at 340-nm wavelength with an on–off current ratio of 25.3. Overall, the proposed stretchable bifunctional sensor demonstrates the potential for various applications, including
$e$
-skin, wearable devices, healthcare, and robotics.