ABSTRACT
In recent years, organic electronic materials have been shown to be a promising tool, even transplanted in vivo, for transducing light stimuli to non-functioning retinas. Here we developed a bio-hybrid optoelectronic device consisting of patterned organic polymer semiconductors interfaced with an electrolyte solution in a closed sandwich architecture in order to study the photo-response of photosensitive semiconducting layers or patterns in an environment imitating biological extracellular fluids. We demonstrate an artificial retina model composed of on an array of 42,100 pixels made of three different conjugated polymers via inkjet printing with 110 pixels/mm2 packing density. Photo-sensing through three-colour pixelation allows to resolve incoming light spectrally and spatially. The compact colour sensitive optoelectronic device represents an easy-to-handle photosensitive platform for the study of the photo response of artificial retina systems.
ABSTRACT
Rapid growth of the internet of things and health monitoring systems have stimulated the development of flexible, wearable, and conformal embedded electronics with the unprecedented need for energy storage systems fully adaptable to diverse form factors. Conventional fabrication methods, such as photolithography for electronics and electrode winding/stacking for energy storage systems, struggle as fabrication strategies to produce devices with three-dimensional, stretchable, and conformal form factors. In this study, we demonstrate the fabrication of supercapacitors on 3D objects through inkjet and water-transfer printing. The devices are initially printed on a water-soluble substrate, which is then placed on the surface of water. Once the substrate is dissolved, the level of water is lowered until the devices are transferred on to the submerged 3D object. As a proof of concept, planar supercapacitors constituted of a silver nanoparticle-based current collector, nickel(II) oxide (NiO) nanoparticle-based active electrodes, and ultraviolet-cured triacrylate polymer-based solid-state electrolyte were used as model materials. The conformal supercapacitors showed a maximum areal capacitance of 87.2 mF·cm-2 at a voltage window of 0-1.5 V. Moreover, the concept of water transfer was further explored with a particular focus on wearable applications by transferring the supercapacitors onto the skin of a human subject to realize epidermal energy storage. This new class of conformal electrochemical energy storage offers a new alternative approach toward monolithically integrated/object-tailored energy storage systems that are essential for complex-shaped devices for internet of things and flexible/on-skin electronic applications.
