New LEDs Can Detect Off Food And Lethal Gases

Your smart device could soon be even smarter with a new infrared light emitting diode (LED) that is ‘tuneable’ to different wavelengths of light.

The University of Melbourne, the Lawrence Berkeley National Laboratory, the University of California, Berkeley, and the Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems (TMOS) have come up with a device that could identify a suite of gases, potentially including lethal ones, improving the safety of firefighters, miners, the military, and your local plumber.

Infrared (IR) spectrometers are common laboratory equipment that can identify different materials by analysing their infrared signatures, which is invisible to the human eye. Just like an AM radio can be tuned to different frequencies of radio wave, IR spectrometers can be tuned to different wavelengths, giving a broad-spectrum analysis of a gas sample. However, these machines are bulky and expensive and not usually practical to take out of the laboratory and into the field.

The new technology bonds a thin layer of black phosphorus crystals to a flexible, plastic-like substrate, allowing it to be bent in ways that cause the black phosphorus to emit light of different wavelengths essentially creating a tuneable infrared LED that allows for the detection of multiple materials.

The device placed inside a fridge could send a notification that meat is going off. When pointed at a handbag, it could reveal whether the bag is made of real leather or a cheaper substitute.

Current materials that are used for IR photodetectors and light emitting devices can be difficult to manufacture, in large part due to the need for multiple layers of perfectly linked crystals.