CRANN PI Prof Donegan increasing light efficiency

Prof John Donegan, Head of the School of Physics, TCD, and Principal Investigator in CRANN, working with a team of Spanish, French, and Russian scientists, have developed a new approach to increasing light efficiency. Their paper was published in the journal Angewandte Chemie (2010, 49, No. 40, 7217-7221), one of the premier chemistry journals in the world. Igor Nabiev from the NanoGUNE Research Centre in San Sebastian (Spain), Alexander O. Govorov of Ohio University (USA), and Prof Donegan have successfully equipped the photosynthetic centre from a purple bacterium with a “light-harvesting antenna” consisting of a quantum dot—an inorganic nanocrystal. Professor Nabiev was an SFI Walton Fellow in TCD from 2008-10. CRANN researchers Yury and Aliaksandra Rakovich were major contributors to this work.

Previous synthetic antennas used organic dye molecules, which have the disadvantage of capturing too small a range of wavelengths from sunlight. Donegan and collaborating teams have replaced the organic molecules with fluorescing inorganic quantum dots as antennas. Quantum dots are nanoscopic crystals that are so tiny that in many respects they behave like molecules rather than as macroscopic solid objects. The electronic and optical properties of quantum dots, including the wavelengths that they absorb, can largely be made to order, because these are dependent on the size, shape, and composition of the dot.

The researchers used quantum dots made of cadmium telluride and cadmium selenide, which fluoresce under irradiation while remaining stable in the long term. The size and surface composition were selected so that they could absorb a particularly broad range of sunlight.The researchers were able to couple the quantum-dot antenna to a reaction centre from the photosynthetic system of a purple bacterium. This coupling produced a three-fold increase in the photoresponse of the reaction centre and this new approach may clear a path toward novel synthetic photosynthetic systems.

To read the full paper click here

Back to News Listing