Concept: Researchers from Australia’s ARC Centre of Excellence in Exciton Science (ARC) have discovered a new method that uses solar energy to detect harmful pollutants in the surrounding atmosphere. This can lead to more efficient and sustainable methods of tracking pollutants and protecting biodiversity and human health.

Nature of Disruption: ARC researchers used solar energy to detect methyl iodide, a type of toxic molecule present in certain pesticides and fumigants, which is often unnoticeable. Toxic chemicals like these are being used in a lot of farm products as well as chemical warfare agents. The researchers are using contemporary photovoltaic technology to develop solar cells that can aid in the detection of such compounds. It leverages light to classify toxins and estimate how much of each type is present in the air. The researchers created synthetic nanocrystals based on a perovskite structure using solar technology, which eventually became the basis of the detection system. The toxin in the air reacts with the fluorescent nanocrystals and changes its color depending on the material. The reaction facilitates the exchange of bromide with iodide within the nanocrystal, which results in color change. The color of methyl iodide starts out green, then shifts to yellow, orange, red, and a darker red based on its amount present in the air.

Outlook: Although the use of chemical warfare agents such as sulfur mustard is prohibited worldwide, mankind still relies on other tightly regulated chemicals in agriculture, manufacturing, and everyday lives, like fumigants such as methyl iodide, which is used to control insects and fungi. These fumigants can be toxic to humans and deplete the ozone layer if used incorrectly or in abnormal quantities. Until now, the only way to search for such fumigants was in a lab with complex, specialized instruments, which may not be feasible in real-world situations. Although some inexpensive detection methods have been attempted before, they lacked sensitivity and took too long to produce results. ARC researchers claim that the use of solar energy provides the precision and speed needed to detect methyl iodide. This type of sensing mechanism can also be extended to detect a wide variety of fumigants and chemical agents like tear gas.