Researchers developed an ink that can be used to print tiny 3D generators for low-power wireless sensors.
Thermoelectric devices generate electricity from heat moving within a material from a part that is warmer to a part that is cooler. In other words, it takes advantage of heat gradients. Researchers have been looking for ways to create thermoelectric devices to power things like wireless sensors.
Micro-thermoelectric devices are commercially viable as they harvest electricity from thermal systems. However, existing fabrication techniques have been costly, and most have been in the form of two-dimensional films, which limits the types of possible applications.
Researchers from Ulsan National Institute of Science and Technology have created a new type of ink that can be used to print tiny 3D generators. They discovered that smaller particles and those that bunched into narrow distribution channels produced higher viscosity. They also found that controlling surface oxidation of thermoelectric particles reduced what is known as the screen effect due to additives. The net result was enhancement of rheological properties.
Using this knowledge, researchers created an ink that could be used to print tiny columns (1.4 mms in height and less than 0.5mms in diameter) on top of a silicon chip. They found the device had a power density of 479.0 μW per centimeter squared, which is enough to power a tiny wireless sensor.