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Night-Vision Contact Lenses 'Now Possible'
Night-vision contact lenses are a step closer after researchers created a tiny infrared light detector that can run at room temperature.
University of Michigan professor Zhaihui Zhong said the design can be built so thin "it can be stacked on a contact lens or integrated with a cell phone".
The research team said that unlike comparable infrared detectors currently on the market, the detector developed does not need cooling equipment to work.
The team started with graphene, which is a single layer of carbon atoms that can sense the whole infrared spectrum.
But it only absorbs around 2% of the light that hits it, meaning it cannot usually produce a detectable electrical signal.
Prof Zhong said: "The challenge for the current generation of graphene-based detectors is that their sensitivity is typically very poor.
"It's a hundred to a thousand times lower than what a commercial device would require."
The team looked for a new way of generating the signal, and came up with "a new way to detect light".
They put an insulating barrier layer between two graphene sheets, and ran a current through the bottom layer.
The technique "allows the sensitivity of a room-temperature graphene device to compete with that of cooled mid-infrared detectors for the first time".
It is currently the size of a small fingernail, but the team say it can be easily scaled down.
Prof Zhong said: "If we integrate it with a contact lens or other wearable electronics, it expands your vision.
"It provides you another way of interacting with your environment."
In January this year Google unveiled a contact lens for diabetics which monitors blood sugar levels.