Marie Curie Actions: Inspiring Researchers - Imdea

Mirror,mirror on the wallThe technology is based on the phenomenon that hydrogencan trigger changes in structural, optical and electric propertiesof rare earth metals such as gadolinium, an element used in avariety of applications ranging from nuclear reactors to compactdisks. For the switch to occur, the inner side of two glass panesmust be coated with a thin fi lm containing gadolinium or asimilar substance. When a gas with small amounts of hydrogenis introduced between them, the properties will change andturn the material’s status from transparent to refl ective. Why isthis useful? Switchable mirrors have applications as windowsin buildings, cars and planes, and can help save energy orsimply act as a screen.Professor Mehta’s Nanoswitch vision was to improve thequality of such switchable mirrors with the help of innovativenanotechnology. The physicist from the Indian Institute ofTechnology Delhi and his colleagues at the Marie Curie host,the Faculty of Engineering at the University of Duisburg-Essenin Germany, had mapped out a route to better switchablemirrors. Most importantly, the professor aimed to develop anew deposition technique for the thin fi lm that would makesure that the rare earth metal nanoparticles would be perfectlyspherical and stay within a well-defi ned size range of 10 to30 nanometres (nm). This, Professor Mehta surmised, wouldimprove the switchable mirror and sensing characteristics ofthe material.More control for greater efficiencyAnd this is exactly what the researchers achieved. They cameup with a sophisticated technique to deposit the thin-fi lmcomposites – made up of rare earth metals and palladium(Pd) nanoparticles – in an even, defect-free way, substantiallyimproving the material’s quality. The novelty of the set-up liesin the extreme control it allows over the material, ProfessorMehta explains. The particles that are irregular in size andshape at the beginning of the process are transformed intouniform, spherical, single-crystal nanoparticles before they arefi nally deposited on the devices.Professor Dr B. R. Mehta (Marie Curie Fellow) and Professor Dr F. E. Kruis (Host Professor) discussing the design of the deposition system,some parts of which can be seen in the background.209