Heat transistor

70 years ago, a discovery was made at Bell Labs in New Jersey that changed the course of human civilization. Three researchers — Shockley, Bardeen, and Brattain — created a switch with no moving parts. By applying a current to one lead, they could control the electricity flowing through the other two leads, and the transistor was born. This was the basis for solid state electronics, and as we learned to cram more and more transistors into smaller and smaller spaces, it was possible to create the microprocessors and memory chips and flat screen televisions and other digital electronics that we take for granted today.

A new development in transistor design could also have an enormous impact. Researchers at Linkoping University in Sweden have created a transistor driven by heat. Using a liquid electrolyte that uses small ions and larger polymer molecules, they are able to create a voltage difference across the two sides of the device. This voltage can then be used to control a circuit, using the heat as a signal. According to the scientists, this device is 100 times more sensitive than traditional thermoelectric materials.

The result is a smart sensor that detects small differences in temperature that can then trigger a device. The potential applications range from night vision systems to smart bandages that monitor the temperature across a wide area as a wound heals. It could also be used to control wearable devices, harvesting the body heat of the wearer in order to control the device’s operation.