Explore the vast range of titles available.

Although electrochemical capacitors (ECs), also known as supercapacitors or ultracapacitors, charge and discharge faster than batteries, they are still limited by low energy densities and slow rate capabilities. We used a standard LightScribe DVD optical drive to do the direct laser reduction of graphite oxide films to graphene. The produced films are mechanically robust, show high electrical conductivity (1738 Siemens per meter) and specific surface area (1520 square meters per gram), and can thus be used directly as EC electrodes without the need for binders or current collectors, as is the case for conventional ECs. Devices made with these electrodes exhibit ultrahigh energy density values in different electrolytes while maintaining the high power density and excellent cycle stability of ECs. Moreover, these ECs maintain excellent electrochemical attributes under high mechanical stress and thus hold promise for high-power, flexible electronics.

A remarkable feature of modern silicon electronics is its ability to remain physically invariant, almost indefinitely for practical purposes. Although this characteristic is a hallmark of applications of integrated circuits that exist today, there might be opportunities for systems that offer the opposite behavior, such as implantable devices that function for medically useful time frames but then completely disappear via résorption by the body. We report a set of materials, manufacturing schemes, device components, and theoretical design tools for a silicon-based complementary metal oxide semiconductor (CMOS) technology that has this type of transient behavior, together with integrated sensors, actuators, power supply systems, and wireless control strategies. An implantable transient device that acts as a programmable nonantibiotic bacteriocide provides a system-level example.

Nanomaterial: power dresser Nanodevices don't use much energy, and if the little they do need can be scavenged from vibrations associated with foot steps, heart beats, noises and air flow, a whole range of applications in personal electronics, sensing and defence technologies opens up. Energy gathering of that type requires a technology that works at low frequency range (below 10 Hz), ideally based on soft, flexible materials. A group working at Georgia Institute of Technology has now come up with a system that converts low-frequency vibration/friction energy into electricity using piezoelectric zinc oxide nanowires grown radially around textile fibres. By entangling two fibres and brushing their associated nanowires together, mechanical energy is converted into electricity via a coupled piezoelectric-semiconductor process. This work shows a potential method for creating fabrics which scavenge energy from light winds and body movement. A self-powering nanosystem that harvests its operating energy from the environment is an attractive proposition for sensing, personal electronics and defence technologies 1 . This is in principle feasible for nanodevices owing to their extremely low power consumption 2 , 3 , 4 , 5 . Solar, thermal and mechanical (wind, friction, body movement) energies are common and may be scavenged from the environment, but the type of energy source to be chosen has to be decided on the basis of specific applications. Military sensing/surveillance node placement, for example, may involve difficult-to-reach locations, may need to be hidden, and may be in environments that are dusty, rainy, dark and/or in deep forest. In a moving vehicle or aeroplane, harvesting energy from a rotating tyre or wind blowing on the body is a possible choice to power wireless devices implanted in the surface of the vehicle. Nanowire nanogenerators built on hard substrates were demonstrated for harvesting local mechanical energy produced by high-frequency ultrasonic waves 6 , 7 . To harvest the energy from vibration or disturbance originating from footsteps, heartbeats, ambient noise and air flow, it is important to explore innovative technologies that work at low frequencies (such as <10 Hz) and that are based on flexible soft materials. Here we present a simple, low-cost approach that converts low-frequency vibration/friction energy into electricity using piezoelectric zinc oxide nanowires grown radially around textile fibres. By entangling two fibres and brushing the nanowires rooted on them with respect to each other, mechanical energy is converted into electricity owing to a coupled piezoelectric–semiconductor process 8 , 9 . This work establishes a methodology for scavenging light-wind energy and body-movement energy using fabrics.

We report classes of electronic systems that achieve thicknesses, effective elastic moduli, bending stiffnesses, and areal mass densities matched to the epidermis. Unlike traditional wafer-based technologies, laminating such devices onto the skin leads to conformal contact and adequate adhesion based on van der Waals interactions alone, in a manner that is mechanically invisible to the user. We describe systems incorporating electrophysiological, temperature, and strain sensors, as well as transistors, light-emitting diodes, photodetectors, radio frequency inductors, capacitors, oscillators, and rectifying diodes. Solar cells and wireless coils provide options for power supply. We used this type of technology to measure electrical activity produced by the heart, brain, and skeletal muscles and show that the resulting data contain sufficient information for an unusual type of computer game controller.

Solar cells are attractive candidates for clean and renewable power; with miniaturization, they might also serve as integrated power sources for nanoelectronic systems. The use of nanostructures or nanostructured materials represents a general approach to reduce both cost and size and to improve efficiency in photovoltaics. Nanoparticles, nanorods and nanowires have been used to improve charge collection efficiency in polymer-blend and dye-sensitized solar cells, to demonstrate carrier multiplication, and to enable low-temperature processing of photovoltaic devices. Moreover, recent theoretical studies have indicated that coaxial nanowire structures could improve carrier collection and overall efficiency with respect to single-crystal bulk semiconductors of the same materials. However, solar cells based on hybrid nanoarchitectures suffer from relatively low efficiencies and poor stabilities. In addition, previous studies have not yet addressed their use as photovoltaic power elements in nanoelectronics. Here we report the realization of p-type/intrinsic/n-type (p-i-n) coaxial silicon nanowire solar cells. Under one solar equivalent (1-sun) illumination, the p-i-n silicon nanowire elements yield a maximum power output of up to 200 pW per nanowire device and an apparent energy conversion efficiency of up to 3.4 per cent, with stable and improved efficiencies achievable at high-flux illuminations. Furthermore, we show that individual and interconnected silicon nanowire photovoltaic elements can serve as robust power sources to drive functional nanoelectronic sensors and logic gates. These coaxial silicon nanowire photovoltaic elements provide a new nanoscale test bed for studies of photoinduced energy/charge transport and artificial photosynthesis, and might find general usage as elements for powering ultralow-power electronics and diverse nanosystems.

The combining microelectronic devices and associated technologies onto a single silicon chip poses a substantial challenge. However, in recent years, the area of silicon photonics has experienced remarkable advancements and notable leaps in performance. The performance of silicon on insulator (SOI) based photonic devices, such as fast silicon optical modulators, photonic transceivers, optical filters, etc., have been discussed. This would be a step forward in creating standalone silicon photonic devices, strengthening the possibility of single on-chip nanophotonic integrated circuits. Suppose an integrated silicon photonic chip is designed and fabricated. In that case, it might drastically modify these combined photonic component costs, power consumption, and size, bringing substantial, perhaps revolutionary, changes to the next-generation communications sector. Yet, the monolithic integration of photonic and electrical circuitry is a significant technological difficulty. A complicated set of factors must be carefully considered to determine which application will have the best chance of success employing silicon-based integrated product solutions. The processing limitations connected to the current process flow, the process generation (sometimes referred to as lithography node generation), and packaging requirements are a few of these factors to consider. This review highlights recent developments in integrated silicon photonic devices and their proven applications, including but not limited to photonic waveguides, photonic amplifiers and filters, on-chip photonic transceivers, and the state-of-the-art of silicon photonic in multidimensional quantum systems. The investigated devices aim to expedite the transfer of silicon photonics from academia to industry by opening the next phase in on-chip silicon photonics and enabling the application of silicon photonic-based devices in various optical systems.

Complex and dynamic control of radiated fields are advantageous for flexible radio systems, which naturally move, roll, bend, twist, deform, and vibrate. Practical challenges hinder the proliferation of these antenna arrays. This work shows how using radio-frequency microchips reduces system component count, decreases mass to ~0.1 g cm −2 , and increases functionality and mechanical flexibility. We develop a general platform for large scale flexible arrays and demonstrate two different 256-elements, 30 × 30 cm 2 flexible arrays. By varying supply distribution methods and radiators we show how performance can be optimized for maximum power delivery or physical flexibility. The demonstrated systems conform to curved surfaces with radii of curvatures as low as 23 cm and wirelessly deliver ~ 80 mW of DC power to a 6.7 cm × 11 cm-receiver over one meter away. This paves the way towards the integration of smart arrays in flexible wearables and deployable lightweight airborne systems.

In this study, a Sn37Pb solder joint was subjected to mechanical loading (constant 5 N force applied in the vertical direction) for a duration of 400 h in order to investigate the evolution of micro-voids. Under electromechanical loading, micro-voids exhibited growth and subsequent shrinkage. Solder joint resistance initially increased and then decreased. The decrease in void volume and the reduction in solder joint resistance are both attributed to the creep deformation occurring in the vertical direction of the solder joint. Notably, no significant element migration was observed within the solder joints after 400 h of loading. The significant stress gradients within the solder joints result in increased back stress, thus balancing the electromigration stress and completely suppressing element migration.