Recyclable Thin-Film Soft Electronics for Smart Packaging and E-Skins.

Despite advances in soft, sticker-like electronics, few efforts have dealt with the challenge of electronic waste. Here, this is addressed by introducing an eco-friendly conductive ink for thin-film circuitry composed of silver flakes and a water-based polyurethane dispersion. This ink uniquely combines high electrical conductivity (1.

Triple crosslinking conductive hydrogels with digitally printable and outstanding mechanical stability for high-resolution conformable bioelectronics.

Soft, conductive, and stretchable hydrogels offer a broad variety of applications, including skin-interfacing electrodes, biomonitoring patches, and electrostimulation. Despite rapid developments over the last decades, a combination of good electrical and mechanical properties, low-cost fabrication, and biocompatibility is yet to be demonstrated. Also, the current methods for deposition and patterning of these hydrogels are manual, and there is a need toward autonomous and digital fabrication techniques.

3R Electronics: Scalable Fabrication of Resilient, Repairable, and Recyclable Soft-Matter Electronics.

E-waste is rapidly turning into another man-made disaster. It is proposed that a paradigm shift toward a more sustainable future can be made through soft-matter electronics that are resilient, repairable if damaged, and recyclable (3R), provided that they achieve the same level of maturity as industrial electronics. This includes high-resolution patterning, multilayer implementation, microchip integration, and automated fabrication.

Energy access during and post-COVID-19 pandemic in sub-Saharan countries: the case of Ethiopia.

The global COVID-19 pandemic causes hundreds of thousands of deaths and has created a catastrophic economic and health crisis around the World. Transportation, manufacturing industries, business and people's movement came to almost a halt and sharp oil and gas prices reduction were observed. The impact of the pandemic for sub-Saharan countries like Ethiopia, which was already struggling with many economic and social welfare problems, is more evident than in other wealthy nations around the World.

Reversible polymer-gel transition for ultra-stretchable chip-integrated circuits through self-soldering and self-coating and self-healing.

Integration of solid-state microchips into soft-matter, and stretchable printed electronics has been the biggest challenge against their scalable fabrication. We introduce, Pol-Gel, a simple technique for self-soldering, self-encapsulation, and self-healing, that allows low cost, scalable, and rapid fabrication of hybrid microchip-integrated ultra-stretchable circuits. After digitally printing the circuit, and placing the microchips, we trigger a Polymer-Gel transition in physically cross-linked block copolymers substrate, and silver liquid metal composite ink, by exposing the circuits to the solvent vapor.

Bi-Phasic Ag-In-Ga-Embedded Elastomer Inks for Digitally Printed, Ultra-Stretchable, Multi-layer Electronics.

A bi-phasic ternary Ag-In-Ga ink that demonstrates high electrical conductivity, extreme stretchability, and low electromechanical gauge factor (GF) is introduced. Unlike popular liquid metal alloys such as eutectic gallium-indium (EGaIn), this ink is easily printable and nonsmearing and bonds strongly to a variety of substrates. Using this ink and a simple extrusion printer, the ability to perform direct writing of ultrathin, multi-layer circuits that are highly stretchable (max.

Fully Untethered Battery-free Biomonitoring Electronic Tattoo with Wireless Energy Harvesting.

Bioelectronics stickers that interface the human epidermis and collect electrophysiological data will constitute important tools in the future of healthcare. Rapid progress is enabled by novel fabrication methods for adhesive electronics patches that are soft, stretchable and conform to the human skin. Yet, the ultimate functionality of such systems still depends on rigid components such as silicon chips and the largest rigid component on these systems is usually the battery.

Untethered Disposable Health Monitoring Electronic Patches with an Integrated AgO-Zn Battery, a AgInGa Current Collector, and Hydrogel Electrodes.

Stretchable electronics stickers that adhere to the human skin and collect biopotentials are becoming increasingly popular for biomonitoring applications. Such stickers include electrodes, stretchable interconnects, silicon chips for processing and communication, and batteries. Here, we demonstrate a material architecture and fabrication technique for a multilayer, stretchable, low-cost, rapidly deployable, and disposable sticker that integrates skin-interfacing hydrogel electrodes, stretchable interconnects, and a AgO-Zn (silver oxide-zinc) battery.

Soft Bioelectronic Stickers: Selection and Evaluation of Skin-Interfacing Electrodes.

Surface biopotentials collected from the human epidermis contain important information about human physiology, such as muscular, heart, and brain activities. However, commercially available wearable biomonitoring devices are generally composed of rigid hardware incompatible with the mechanical compliance of soft human tissues. Thin-film stretchable e-skin circuits that can interface the human skin represent an excellent alternative for long-term wearable biomonitoring.

Reliable interfaces for EGaIn multi-layer stretchable circuits and microelectronics.

We tackle two well-known problems in the fabrication of stretchable electronics: interfacing soft circuit wiring with silicon chips and fabrication of multi-layer circuits. We demonstrate techniques that allow integration of embedded flexible printed circuit boards (FPCBs) populated with microelectronics into soft circuits composed of liquid metal (LM) interconnects. These methods utilize vertical interconnect accesses (VIAs) that are produced by filling LM alloy into cavities formed by laser ablation.

Hydroprinted Electronics: Ultrathin Stretchable Ag-In-Ga E-Skin for Bioelectronics and Human-Machine Interaction.

We introduce a soft ultrathin and stretchable electronic skin with surface-mounted components that can be transferred and wrapped around any three-dimensional (3D) surface or self-adhere to the human skin. The ∼5 μm thick circuit is fabricated by printing the pattern over a temporary tattoo paper using a desktop laser printer, which is then coated with a silver ink and eutectic gallium-indium (EGaIn) liquid metal alloy. The resulting "Ag-In-Ga" traces are highly conductive and maintain low electrical resistivity as the circuit is stretched to conform to nondevelopable 3D surfaces.

EGaIn-Assisted Room-Temperature Sintering of Silver Nanoparticles for Stretchable, Inkjet-Printed, Thin-Film Electronics.

Coating inkjet-printed traces of silver nanoparticle (AgNP) ink with a thin layer of eutectic gallium indium (EGaIn) increases the electrical conductivity by six-orders of magnitude and significantly improves tolerance to tensile strain. This enhancement is achieved through a room-temperature "sintering" process in which the liquid-phase EGaIn alloy binds the AgNP particles (≈100 nm diameter) to form a continuous conductive trace. Ultrathin and hydrographically transferrable electronics are produced by printing traces with a composition of AgNP-Ga-In on a 5 µm-thick temporary tattoo paper.