Who is not impressed by the play of colors that opals and other gemstones create?
Inspired by the interaction of opals with light, Dr. Alexander Kühne investigates and develops artificial opals for future applications in the fields of telecommunication, photonics and biomedicine. His efforts find appreciation: The Federal Ministry of Education and Research (BMBF) now decided to fund Alexander Kühne’s junior research group at DWI – Leibniz Institute for Interactive Materials. The total funding amount is one million euros and covers a period of four years.
Opals – both natural and artificial ones – consist of small particles that can alter light waves. For example, they reflect light of a certain wavelength, whereas light of a different wavelength can pass. In his group, Alexander Kühne prepares such particles in a sophisticated chemical procedure. Subsequently, the group members use a spinning method to prepare light-conducting fibers, in which the particles assemble in the core.
Alternatively, they can use ink jet printing to position the particles on a surface. Both techniques are based on the property of the particles to self-assemble into regular crystalline structures just like in natural opals. “With our particle system, we combine three distinct ways of interaction with light,” 33-year-old Kühne explains. “Light absorption like in dyes and pigments, emission using the fluorescence effect, and reflection occurring from the regular structure of the assembled particles.”
“In the future, our materials may play a significant role as manipulators in light-guiding data cables. They might contribute to faster, more efficient ways of data transfer. In addition, they could be used as printable forgery protection labels, on packaging of drugs and vaccines.“ However, current challenges for Kühne and his team are still a few steps away from application: “We are trying to create high numbers of particles with uniform size and morphology. Besides, we are working on combining several fluorescent colors within one system.“
Alexander Kühne studied chemistry in Cologne and Glasgow and did his PhD in the group of Richard Pethrick at the University of Strathclyde in Glasgow. After postdoc positions in the labs of Klaus Meerholz (Cologne) and David Weitz (Harvard), he moved back to Germany and joined DWI in 2011. His current research is based on his experience with nano-structured polymer films for organic lasers.
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