Researchers have developed a miniscule colloidal quantum dot spectrometer that can be fitted inside smartwatches and smartphones.

What does this mean? Not only lighter smartphones and wearables, but devices that are able to assist people in assessing whether they suffer from skin cancer through apps such as SkinVision.

The mini spectrometer is the handiwork of a team of scientists from China's Tsinghua University and Massachusetts Institute of Technology (MIT) who created the device by substituting the traditionally used interferometric optics. What did they replace it with? A filter that is made up of colloidal quantum dots, i.e. nanocrystals, which are composed of a several metal combinations.

For those wondering what a spectrometer is, this device is able to take electromagnetic waves and separates the different light wavelengths, detecting their properties like polarity and intensity. Scientists use spectrometers to aid them in the analysis of light in biological, physical and chemical research work.

The use of quantum dots in spectrometers helps in the absorption of different light wavelengths, which is hinged on the composition of the dot. When one places a slim film of these nanocrystals over a smartphone's camera which has photo detection capabilities, for example, the algorithms decode the entering light to ascertain the original light source's properties.

For the purpose of the study, the researchers tested the spectrometer prototype with 195 quantum dots, which were able to make different readings. The resolution deployed by the scientists was a tad lower than the one used by traditional spectrometers.

"Spectroscopy is carried out in almost every field of science, whenever light interacts with matter. Although sophisticated instruments with impressive performance characteristics are available, much effort continues to be invested in the development of miniaturised, cheap and easy-to-use systems," note the researchers in the paper.

A gamut of applications such as monitoring marine systems, NASA's Curiosity Rover and respiratory gas analysis devices in hospitals currently deploy spectrometers.

The researchers are optimistic that the quantum dot spectrometer will aid in the diagnosis of skin ailments, detection of UV levels and environmental pollutants and analysis of urine samples, among other medical uses. 

The spectrometer is the size of a quarter and uses production materials that cost a few dollars. These factors will lure space agencies and manufacturers alike.

Jie Bao, the study's lead author also waxes eloquent of the device's performance even in the research stages and says it is "close to a real product." He is also hopeful of the quantum dot spectrometers being deployed in smartphones in the near term.

The study is published in the journal Nature.

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