Organic sensors shine hot and cold

Researchers in Abu Dhabi and China have reported the first instance of using organic (carbon-based) crystals for temperature sensing devices. This significantly widens the options for making novel temperature sensors, especially for extreme environments, including space.

“Organic materials have hardly been explored for functional devices in the past,” says Panče Naumov, whose team at New York University Abu Dhabi came up with the idea of organic temperature sensors with collaborators at Jilin University, in China. The work also drew on collaboration with researchers at Sorbonne University Abu Dhabi.

Naumov says that the elastic flexibility of organic materials is emerging as a major advantage to avoid damage due to the vibrations and cracking that can affect conventional devices, especially in extreme temperatures, such as the coldness of space. Organic materials are also very light, which can be a vital requirement for some applications.

The new approach is based on organic molecules that, when excited by laser light, fluoresce at different wavelengths, and therefore different colours, depending on temperature. The crystalline compounds displayed temperature dependence of their fluorescent wavelength across a very wide range, especially at low temperatures down to -196 °C.

“They tick most of the boxes of requirement for an ideal optical sensing material,” says Naumov.

Developing the innovative materials was not easy. Naumov explains that organic crystals are particularly difficult to manipulate and process, requiring “special skills and a lot of patience”.

The team’s next challenge is to improve control of crystal fabrication to optimize their size and shape and couple them with other sensor components. Since the crystals are very small, this will require miniaturization of all other parts of any devices.

“We look forward to working with our collaborators to optimize and generalize the approach using a variety of organic crystals,” Naumov says.

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