Tellurium nanoparticles achieve dielectric properties when exposed to sunlight

Typical morphology and structure characterization results of Te nanoparticles prepared by ns-LAL. Credit: Science Advances (2018). DOI: 10.1126/sciadv.aas9894

A team of researchers at Sun Yat-sen University in China has created a material with dual solar properties by adding tellurium nanoparticles to water—it showed both plasmonic-like and all-dielectric properties when exposed to sunlight. In their paper published in the journal Science Advances, the group describes their material and its possible uses.

As the search for renewable resources continues, some in the field have turned to study the possibility of adding materials to water to make it easier to produce steam for driving a turbine. Several years ago, one team of researchers discovered that adding nanoparticles to water could cause it to produce steam when exposed to sunlight. Since that time, scientists have continued experimenting with adding nanomaterials. Meanwhile, other experiments have suggested that plasmonics could play a role in photothermal conversion. In this new effort, the researchers have found a material that allows nanoparticles to offer the benefits of both approaches.

The work by the team in China was straightforward. They created nanoparticles made out of tellurium and then mixed them into a container filled with water and tested the result to see what changes it might have wrought.

The researchers report that adding the nanoparticles improved the evaporation rate by a factor of three. Testing showed that they could raise its temperature from 29°C to 85°C in just 100 seconds by shining sunlight on it. The researchers found that this improvement was possible because the nanoparticles behaved like plasmonic nanoparticles—but only when smaller sized nanoparticles (less than 120 nanometers) were involved. Nanoparticles that were larger than 120 nanometers behaved like an all-dielectric. Mixing nanoparticles of both sizes into the same container of water allowed the sample to take on both characteristics—the team claims the resultant material is the first to demonstrate both properties.

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