While television, film, and video games tend to associate infrared cameras with tracking people, those complicated devices have many more uses, thanks to how much the world changes when viewed in infrared. A large part of why those detectors are so complicated is that they must house a cooling system for the sensor to operate properly. Researchers at the University of Michigan however, have successfully built a detector based on graphene that can sensor the full infrared spectrum, at room temperature.
Graphene is an atom-thick sheet of carbon with extraordinary properties, and is known to be able to sense the whole of infrared light. Its use in sensor has been limited though, because being an atom thickness, it only absorbs 2.3% of the light that hits it, and does not generate a strong enough electrical current to be detected. The Michigan researchers managed to overcome that issue by using some quantum mechanics. The researchers put an insulating layer between two sheets of graphene, with a current running through the bottom one. When an infrared photon strikes the top one, an electron would be freed and then tunnel through the insulator, to the bottom layer. This left a positively charged hole, which creates an electric field that alters the electric current in a detectable way.
Unlike the cooled detectors you can find today, this sensor is smaller than a pinky nail and can actually be scaled down. Potentially arrays of them could be used to create full-spectrum infrared cameras, and we could even see them integrated into contact lenses.
Source: University of Michigan