For years, scientists and engineers have worked to design electronics which can interface with the body. However, typical silicon wafer-based electronics, which are planar and stiff, are not suited to interface with the soft, curvilinear, and dynamic environment that biology presents. By exploiting the features of shape-memory polymer (SMP) substrates, an international team of researchers has now demonstrated a unique form of adaptive electronics which softly conform or deploy into 3D shapes after exposure to a stimulus. The resulting organic thin-film transistors (OTFTs) can change their mechanical properties from rigid and planar, to soft and compliant, in order to enable soft and conformal wrapping around 3D objects, including biological tissue.
Taking the approach of flexible electronics one step further, researchers now have integrated all-carbon based electronic devices to live plants and insects. They developed an unconventional approach for the in situ synthesis of monolithically integrated electronic devices based on single-walled carbon nanotube channels and graphitic electrodes. The highly flexible transistors were formed directly by the in situ synthesis using patterned metal catalyst films and subsequently could be transferred to both planar and nonplanar substrates, including papers, clothes, and fingernails.
Most of the accomplishments in building carbon nanotube circuits have come at the single-nanotube level. Researchers have been struggling with two major obstacles in building CNT-based circuits: the presence of metallic CNTs and a 'perfect' alignment of nanotubes. In new work, researchers have now demonstrated the ability to fabricate, in a scalable manner, larger-scale CNFET circuits at highly scaled technology nodes. The channel lengths are ranging from 90 nm to sub-20 nm.
Scientists have great expectations that nanotechnologies will bring them closer to the goal of creating computer systems that can simulate and emulate the brain's abilities for sensation, perception, action, interaction and cognition while rivaling its low power consumption and compact size - basically a brain-on-a-chip. Already, scientists are working hard on laying the foundations for what is called neuromorphic engineering - a new interdisciplinary discipline that includes nanotechnologies and whose goal is to design artificial neural systems with physical architectures similar to biological nervous systems.
Stretchable energy storage and conversion devices are key components for the fabrication of complete and independent stretchable systems. A recent review summarizes the recent progresses in the developments of stretchable power sources including supercapacitors, batteries and solar cells. It discusses representative structural and material designs to impart stretchability to the originally rigid devices and analyze advantages and drawbacks associated with the various fabrication methods. It also presents summaries of the research progresses along with future development directions.
Flexible electronics is a rising field in terms of research and potential application opportunities to obtain similar characteristics than today's prevailing rigid electronics components. In new work, researchers have demonstrated the semiconductor industry's most advanced device architecture - FinFET, a new generation of device architecture which Intel has adopted in 2011 in their microprocessors; these field effect transistors offer non-planar three-dimensional topology where the channels are vertically aligned in arrays of ultra-thin silicon fins bordered by multiple gates - in a flexible platform using only industry standard processes and keeping the advantages offered by silicon.
Researchers report the fabrication of flexible, durable, and self-assembled graphene textile electrodes for supercapacitors using a novel wet-spinning approach of ultra large graphene oxide liquid crystals followed by heat-treatment to obtain graphene fibers. The key to producing such fibers and yarns is to preserve the large sheet size even after the reduction of GO while simultaneously maintaining a high interlayer spacing in between graphene sheets. These graphene yarns could lead the way to the realization of powerful next-generation multifunctional renewable wearable energy storage systems.
The term printed electronics refers to the application of printing technologies for the fabrication of electronic circuits and devices, increasingly on flexible plastic or paper substrates. Traditionally, electronic devices are mainly manufactured by photolithography, vacuum deposition, and electroless plating processes. In contrast to these multistaged, expensive, and wasteful methods, inkjet printing offers a rapid and cheap way of printing electrical circuits with commodity inkjet printers and off-the-shelf materials.