Silver nanowires (AgNWs) have emerged as a promising nanomaterial for next generation stretchable electronics. However, until now, the fabrication of AgNWbased components has been hampered by complex and time-consuming steps. Here, we introduce a facile, fast, and one-step methodology for the fabrication of highly conductive and stretchable AgNW/polyurethane (PU) composite electrodes based on a high-intensity pulsed light (HIPL) technique. HIPL simultaneously improved wire-wire junction conductivity and wire-substrate adhesion at room temperature and in air within 50 μs, omitting the complex transfer-curing-implanting process. Owing to the localized deformation of PU at interfaces with AgNWs, embedding of the nanowires was rapidly carried out without substantial substrate damage. The resulting electrode retained a low sheet resistance (high electrical conductivity) of <10 Ω/sq even under 100% strain, or after 1,000 continuous stretching-relaxation cycles, with a peak strain of 60%. The fabricated electrode has found immediate application as a sensor for motion detection. Furthermore, based on our electrode, a light emitting diode (LED) driven by integrated stretchable AgNW conductors has been fabricated. In conclusion, our present fabrication approach is fast, simple, scalable, and costefficient, making it a good candidate for a future roll-to-roll process.

The development of flexible and stretchable sensors has been receiving increasing attention in recent years. In particular, stretchable, skin-like, wearable sensors are desirable for a variety of potential applications such as personalized health monitoring, human-machine interfaces, and environmental sensing. In this paper, we review recent advancements in the development of mechanically flexible and stretchable sensors and systems that can be used to quantitatively assess environmental parameters including light, temperature, humidity, gas, and pH. We discuss innovations in the device structure, material selection, and fabrication methods which explain the stretchability characteristics of these environmental sensors and provide a detailed and comparative study of their sensing mechanisms, sensor characteristics, mechanical performance, and limitations. Finally, we provide a summary of current challenges and an outlook on opportunities for possible future research directions for this emerging field.

In this paper, transparent electrodes with dense Cu@Ag alloy nanowires embedded in the stretchable substrates are successfully fabricated by a high-intensity pulsed light (HIPL) technique within one step. The intense light energy not only induces rapid mutual dissolution between the Cu core and the Ag shell to form dense Cu@Ag alloy nanowires but also embeds the newly formed alloy nanowires into the stretchable substrates. The combination of alloy nanowires and embedded structures greatly improve the thermal stability of the transparent electrodes that maintain a high conductivity unchanged in both high temperature (140 °C) and high humidity (85 °C, 85% RH) for at least 500 h, which is much better than previous reports. The transparent electrodes also exhibit high electromechanical stability due to the strong adhesion between alloy nanowires and substrates, which remain stable after 1000 stretching–relaxation cycles at 30% strain. Stretchable and transparent heaters based on the alloyed and embedded electrodes have a wide outputting temperature range (up to 130 °C) and show excellent thermal stability and stretchability (up to 60% strain) due to the alloy nanowires and embedded structures. To sum up, this study proposes the combination of alloying and embedding structures to greatly improve the stability of Cu nanowire-based stretchable transparent electrodes, showing a huge application prospect in the field of stretchable and wearable electronics.

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A method to fabricate thermoplastically deformable electronic circuits is presented, with the intent of achieving low-cost 2.5D free-form rigid smart objects. This by utilizing existing flexible circuit technology based stretchable circuits, in combination with thermoplastic materials. After fabricating the circuit in a flat state, a thermoforming step shapes the device by heating it beyond its glass transition temperature, and pushing it against a mold. Preliminary tests show the feasibility to fabricate simple circuits using off-the-shelf circuit components; showing a minimal decrease in conductivity of the polyimide supported copper-based interconnects.