Collecting light with artificial moth eyes
Ammonium tungstate/PSS film surface: (a) SEM picture before pyrolysis; (b & c) SEM picture after pyrolysis. © EMPA
Scientists at EMPA in Zürich and University of Basel have developed a photoelectrochemical cell, recreating a moth’s eye to drastically increase its light collecting efficiency. The cell is made of cheap raw materials – iron and tungsten oxide. Analyses at BESSY II have revealed which chemical processes are useful to facilitate the absorption of light.
Empa researchers Florent Boudoire and Artur Braun have implemented a special microstructure on the photoelectrode surface, which gathers sunlight and does not let it out again. The basis for this innovative structure are tiny particles of tungsten oxide. These yellow microspheres are applied to an electrode and then covered with an extremely thin layer of iron oxide. When light falls on the particles it is internally reflected back and forth, till finally all the light is absorbed. All the entire energy in the beam is now available to use for splitting the water molecules.
In principle the newly conceived microstructure functions like the eye of a moth, explains Florent Boudoire. The eyes of these night active creatures need to collect as much light as possible to see in the dark, and also must reflect as little as possible to avoid detection and being eaten by their enemies. The microstructure of their eyes especially adapted to the appropriate wavelength of light. Empa's photocells take advantage of the same effect.
The swiss team did analyze their samples under the x-ray microscope at BESSY II in order to get detailed information about the absorption of light and the chemical processes which enhance it.
Information of EMPA
Publication in Energy&Environmental Sciences
- Magnon momentum microscopy: A new window into nanoscale spin-wavesAn international team lead by the Max Born Institute has developed a new type of momentum microscopy to image magnons — the quanta of collectively excited spins — directly in two-dimensional reciprocal space using soft X-rays. Measurements have taken place at BESSY II and PETRA III, first author ist the HZB physicist Steffen Wittrock. Owing to its remarkable sensitivity, simplicity, and access to nanometer-scale wavelengths, this novel technique establishes a powerful and versatile platform for exploring nonlinear magnon interactions, which are promising for future computing schemes.
- X-ray analysis reveals overpainted fascist symbolsErich Mercker was a successful painter during the Nazi era and in the years that followed. After 1945, he covered up Nazi symbols in at least one of his paintings. With an interdisciplinary team, physicist Dr Ioanna Mantouvalou reports on this study in the Nature Journal Heritage Science.
- AI agents deliver results – but do they reason scientifically?A research team co-led by Kevin Maik Jablonka from the Helmholtz Institute for Polymers in Energy Applications Jena (HIPOLE Jena) and N. M. Anoop Krishnan from the Indian Institute of Technology Delhi has developed Corral, a new benchmark for AI agents in science. The preprint “AI scientists produce results without reasoning scientifically” has been published on arXiv (https://doi.org/10.48550/arXiv.2604.18805). The analysis shows that current systems can execute scientific workflows and deliver results; however, they often do not follow the basic principles of scientific testing and reasoning.