Nanoparticles shine34x brighter than quantum dots

Mesoporous silicon-dioxide (silica) nanoparticles that claim to be 34-times brighter than the brightest quantum dots have been invented by researchers at Clarkson University in Potsdam, New York, United States.

Transparent silicon-dioxide hulls contain fluorescent nanoparticles instead of using quantum-confinement as quantum dots--previously the brightest nanoparticles--do. This enables the brighter operation, according to the inventors.

The mesoporous silica nanoparticles have potential applications in medicine, biology, material science, and environmental protection, according to Igor Sokolov, Physics professor, Clarkson University, who claims that his brighter particles will allow much finer detection of environmental pollutants, biosensors and homeland defense detectors.

Fluorescent nanoparticles absorb light at one wavelength, then emit it at another. By functionalizing the particles so that they fluoresce only when in the presence of the substance to be detected, ultra-sensitive nanoparticles can detect smaller amounts of the pollutant or toxin that would otherwise be possible.

Sokolov锟絪 process securely seals a large number of organic fluorescent molecules inside nanoporous silicon dioxide hulls, which can range from 20nm to 50nm in diameter. As an example of their brightness, Sokolov claims that nanoparticles of just 40nm in diameter are brighter than 25nm-30nm water-dispersible quantum dots.

The ultra-bright particles were synthesized with the help of postdoctoral fellows Shajesh Palantavida and Eun-Bum Cho (now an assistant professor at Seoul National University of Science and Technology) along with a doctoral candidate at Clarkson, Dmytro Volkov.

Funding for the project was provided by the National Science Foundation and the U.S. Army Research Laboratory's Army Research Office.

- R. Colin Johnson
EE Times