B-PHOT researcher professor Nathalie Vermeulen and her team have discovered a very unexpected and far-reaching trait of graphene, a substance that is seen by many as a game-changing material of the future. Graphene is capable of changing the wavelength of light, and their research showed that instead of strong incoming light intensities as typically employed for this purpose, graphene has a better conversion efficiency for low incoming light intensities.
This breakthrough, achieved in the frame of an international collaboration between B-PHOT and researchers from Poland and China, was recently published in Nature Communications
Because of this finding, compact light sources could be developed with graphene that transmit a wide range of colors. This type of light source could, for example, help diabetic patients to measure their glucose levels painlessly by shining light on the blood veins rather than taking blood samples.
Increasing the accuracy of medical imaging for skin cancer detection can be another potential application based on these research results, as she explained in De Tijd : 'In an ultrasound scan, images are made on the basis of sound waves that are reflected. Something similar is possible with scans based on light, so-called OCT scans. The more colors you can send out, the more detailed the image can be. Some wavelengths are absorbed, others reflected. You can read out this information. Based on those results you can reconstruct a cross-section of your skin with a color scan... Think of skin cancer, where tumors are often close to the surface. You would never be able to detect them with ultrasound technology, but you can do that with a color scan .'
Graphene, a material consisting of only 1 layer of carbon atoms, is considered one of the most important new materials of the 21st century which can be used for various applications ranging from touch screens to solar cells. This broad applicability of graphene is mainly due to its unique electrical and optical properties.
In the framework of her prestigious ERC Starting Grant, awarded by the European Research Council, Nathalie examines how graphene can change the color of light, or how it can realize so-called wavelength conversion. In the process, she and her team discovered the material yields the best conversion efficiencies at low light intensities and not as much at high light intensities, as is usually assumed. This counter-intuitive behavior is the result of very unusual physical phenomena in graphene and opens the way to new applications. This discovery can be used, among other things, to develop compact light sources that radiate a wide range of colors. This type of light source, for example, could be integrated in a watch and measure diabetic patients' glucose levels constantly and painlessly by shining light on the blood vessels.
For more information, please contact Nathalie Vermeulen