Fluorescent materials that react with explosives is one of a few ways airport staff can ensure the safety of travelers, but there's still room for improvement. Scientists have developed a light-up material they claim can more reliably detect explosives in the vicinity, by being a bit more selective about when it changes color.

Previously, many of the polymers used to detect explosives are fluorescent in their normal state. When the light passing through the material interacts with an explosive molecule, it is then released as heat rather than light, meaning the material is no longer fluorescent.

According to scientists at the University of Southern Denmark, there are limitations to this approach. It is not only explosive molecules that can cause the fluorescence to disappear, but other particles too, making for several scenarios that could trigger false alarms.

So the team went the other way. It created a material made from a set of molecules that is not fluorescent in its normal state. But one of the molecules making up the material, TNDCF, has special properties which cause it to become fluorescent only when it interacts with either explosive molecules or very specific salts, such as those based on chlorine or fluorine, thereby reducing the chances of a false alarm.

"There can only be two reasons why it turns fluorescent, one of them being the presence of explosives," explains lead author Bähring. "Thus this material is a highly reliable tool for detecting explosives."

The team hopes that the knowledge gained through developing the material can lead to devices that rely on the same molecules to better detect explosives in airports.

"This new knowledge could lead to creating a small device based on this set of molecules," Bähring says. "With such a device security staff in airports could [for example] test if there are explosives molecules on or near a bag."

The research was published in Chemistry – A European Journal.