Collecting light with artificial moth eyes

Ammonium tungstate/PSS film surface:  (a) SEM picture before pyrolysis; (b & c) SEM picture after pyrolysis.

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
 

EMPA/arö

  • Copy link

You might also be interested in

  • Vortragsreihe zu BIPV auf der Inolope Expo 2025
    Nachricht
    04.02.2025
    Vortragsreihe zu BIPV auf der Inolope Expo 2025
    Das Helmholtz-Zentrum Berlin und BAIP - Beratungsstelle für Bauwerkintegrierte Photovoltaik sind Partner der Inolope Expo 2025 – der Business-Plattform für innovative Gebäudehüllen.

    An unserem Stand 7.F02 laden wir zu Gesprächen  und Informationen zu BIPV ein. An zwei Tagen präsentieren wir praxisorientierte Vorträge zum Thema bauwerkintegrierte Photovoltaik und Insights zu unserem Real-labor Testinghalle. Hier erfahren Sie, wie Sie mit solarer Architektur auf innovative, ästhetische und nachhaltige Weise gestalten.

  • HZB Sets New World Record for CIGS Perovskite Tandem Solar Cells
    News
    04.02.2025
    HZB Sets New World Record for CIGS Perovskite Tandem Solar Cells
    Combining two semiconductor thin films into a tandem solar cell can achieve high efficiencies with a minimal environmental footprint. Teams from HZB and Humboldt University Berlin have now presented a CIGS-perovskite tandem cell that sets a new world record with an efficiency of 24.6%, certified by the independent Fraunhofer Institute for Solar Energy Systems.

  • HZB-magazine lichtblick - the new issue is out!
    News
    31.01.2025
    HZB-magazine lichtblick - the new issue is out!
    In the cover story we introduce Astrid Brandt. She is Head of User Coordination at Helmholtz-Zentrum Berlin. She and her team keep constant track of applications, measurement times and publications of the 1000 guest researchers who come to BESSY II each year.

    She has always been fascinated by science. But she has also never let go of her other passion, which is music.