MMaterialsgateNEWS 2014/04/14

Related MaterialsgateCARDS

Energy: Thermoelectric generator on glass fabric for wearable electronic devices

Wearable computers or devices have been hailed as the next generation of mobile electronic gadgets, from smart watches to smart glasses to smart pacemakers.

For electronics to be worn by a user, they must be light, flexible, and equipped with a power source, which could be a portable, long-lasting battery or no battery at all but a generator. How to supply power in a stable and reliable manner is one of the most critical issues to commercialize wearable devices.

A team of KAIST researchers headed by Byung Jin Cho, a professor of electrical engineering, proposed a solution to this problem by developing a glass fabric-based thermoelectric (TE) generator that is extremely light and flexible and produces electricity from the heat of the human body. In fact, it is so flexible that the allowable bending radius of the generator is as low as 20 mm. There are no changes in performance even if the generator bends upward and downward for up to 120 cycles.

To date, two types of TE generators have been developed based either on organic or inorganic materials. The organic-based TE generators use polymers that are highly flexible and compatible with human skin, ideal for wearable electronics. The polymers, however, have a low power output. Inorganic-based TE generators produce a high electrical energy, but they are heavy, rigid, and bulky.

Professor Cho came up with a new concept and design technique to build a flexible TE generator that minimizes thermal energy loss but maximizes power output. His team synthesized liquid-like pastes of n-type (Bi2Te3) and p-type (Sb2Te3) TE materials and printed them onto a glass fabric by applying a screen printing technique. The pastes permeated through the meshes of the fabric and formed films of TE materials in a range of thickness of several hundreds of microns. As a result, hundreds of TE material dots (in combination of n and p types) were printed and well arranged on a specific area of the glass fabric.

Professor Cho explained that his TE generator has a self-sustaining structure, eliminating thick external substrates (usually made of ceramic or alumina) that hold inorganic TE materials. These substrates have taken away a great portion of thermal energy, a serious setback which causes low output power.

He also commented,

"For our case, the glass fabric itself serves as the upper and lower substrates of a TE generator, keeping the inorganic TE materials in between. This is quite a revolutionary approach to design a generator. In so doing, we were able to significantly reduce the weight of our generator (~0.13g/cm2), which is an essential element for wearable electronics."

When using KAIST's TE generator (with a size of 10 cm x 10 cm) for a wearable wristband device, it will produce around 40 mW electric power based on the temperature difference of 31 °F between human skin and the surrounding air.

Professor Cho further described about the merits of the new generator:

"Our technology presents an easy and simple way of fabricating an extremely flexible, light, and high-performance TE generator. We expect that this technology will find further applications in scale-up systems such as automobiles, factories, aircrafts, and vessels where we see abundant thermal energy being wasted."

This research result was published online in the March 14th issue of Energy & Environmental Science and was entitled "Wearable Thermoelectric Generator Fabricated on Glass Fabric."

Source: The Korea Advanced Institute of Science and Technology (KAIST) - 10.04.2014.

Investigated and edited by:

Dr.-Ing. Christoph Konetschny, Inhaber und Gründer von Materialsgate
Büro für Material- und Technologieberatung
The investigation and editing of this document was performed with best care and attention.
For the accuracy, validity, availability and applicability of the given information, we take no liability.
Please discuss the suitability concerning your specific application with the experts of the named company or organization.

You want additional material or technology investigations concerning this subject?

Materialsgate is leading in material consulting and material investigation.
Feel free to use our established consulting services

MMore on this topic

Researchers from North Carolina State University have developed a new, stretchable antenna that can be incorporated into wearable technologies, such as health monitoring devices.

“Many researchers – including our lab – have developed prototype sensors for wearable health systems, but there was a clear need to develop antennas that can be easily incorporated into those systems to transmit data from the sensors, so that patients can be monitored or diagnosed,” says Dr. Yong Zhu, an associate professor of mechanical and aerospace engineering at NC State and senior author of a paper describing the work. The researchers wanted to develop an antenna that could be stretched, rolled or twisted and always return to its original shape, because wearable systems can be subject to a variety of stresses as patients move around. To create an appropriately resilient, effective... more read more

Most modern electronics, from flat-screen TVs and smartphones to wearable technologies and computer monitors, use tiny light-emitting diodes, or LEDs. These LEDs are based off of semiconductors that emit light with the movement of electrons. As devices get smaller and faster, there is more demand for such semiconductors that are tinier, stronger and more energy efficient.

University of Washington scientists have built the thinnest-known LED that can be used as a source of light energy in electronics. The LED is based off of two-dimensional, flexible semiconductors, making it possible to stack or use in much smaller and more diverse applications than current technology allows. “We are able to make the thinnest-possible LEDs, only three atoms thick yet mechanically strong. Such thin and foldable LEDs are critical for future portable and integrated electronic devices,” said Xiaodong Xu, a UW assistant professor in materials science and engineering and in physics. Xu along with Jason Ross, a UW materials science and engineering graduate student, co-authored... more read more

Researchers at the Korea Advanced Institute of Science and Technology (KAIST) developed K-Glass, a wearable, hands-free HMD that enables users to find restaurants while checking out their menus.

Walking around the streets searching for a place to eat will be no hassle when a head-mounted display (HMD) becomes affordable and ubiquitous. Researchers at the Korea Advanced Institute of Science and Technology (KAIST) developed K-Glass, a wearable, hands-free HMD that enables users to find restaurants while checking out their menus. If the user of K-Glass walks up to a restaurant and looks at the name of the restaurant, today’s menu and a 3D image of food pop up. The Glass can even show the number of tables available inside the restaurant. K-Glass makes this possible because of its built-in augmented reality (AR) processor. Unlike virtual reality which replaces the real world with a... more read more

Though some people already seem inseparable from their smartphones, even more convenient, wearable, solar-powered electronics could be on the way soon, woven into clothing fibers or incorporated into watchbands. This novel battery development, which could usher in a new era of “wearable electronics,” is the topic of a paper in the ACS journal Nano Letters.

Taek-Soo Kim, Jung-Yong Lee, Jang Wook Choi and colleagues explain that electronic textiles have the potential to integrate smartphone functions into clothes, eyeglasses, watches and materials worn on the skin. Possibilities range from the practical — for example, allowing athletes to monitor vital signs — to the aesthetic, such as lighting up patterns on clothing. The bottleneck slowing progress toward development of a wider range of flexible e-fabrics and materials is the battery technology required to power them. Current wearable electronics, such as smartwatches and Google Glass, still require a charger with a cord, and already-developed textile batteries are costly and impractical... more read more


Partner of the Week

Search in MaterialsgateNEWS

Books and products