Université de Fribourg

Carbon‐assisted stable silver nanostructures

Abdollahi, S. Narjes ; Ochoa Martínez, Efraín ; Kilchoer, Cédric ; Kremer, Geoffroy ; Jaouen, Thomas ; Aebi, Philipp ; Hellmann, Tim ; Mayer, Thomas ; Gu, Yibei ; Wiesner, Ulrich B. ; Steiner, Ullrich ; Wilts, Bodo D. ; Gunkel, Ilja

In: Advanced Materials Interfaces, 2020, vol. 7, no. 23, p. 2001227

Nanostructured silver stands out among other plasmonic materials because its optical losses are the lowest of all metals. However, nanostructured silver rapidly degrades under ambient conditions, preventing its direct use in most plasmonic applications. Here, a facile and robust method for the preparation of highly stable nanostructured silver morphologies is introduced. 3D nanostructured...

Université de Fribourg

Polymerization‐induced wrinkled surfaces with controlled topography as slippery surfaces for colorado potato beetles

Bergmann, Johannes B. ; Moatsou, Dafni ; Surapaneni, Venkata A. ; Thielen, Marc ; Speck, Thomas ; Wilts, Bodo D. ; Steiner, Ullrich

In: Advanced Materials Interfaces, 2020, p. 2000129

Controlling the interaction of insect populations with their host plants has recently received renewed attention in the light of pest control. One way to modify the interaction of insects with their host plants in a non‐chemical way is through influence of their de/attachment. Insect detachment has been observed for textured biological and structured artificial surfaces with morphologies ...

Université de Fribourg

Polydopamine nanoparticle doped nanofluid for solar thermal energy collector efficiency increase

Hauser, Daniel ; Steinmetz, Lukas ; Balog, Sandor ; Taladriz‐Blanco, Patricia ; Septiadi, Dedy ; Wilts, Bodo D. ; Petri‐Fink, Alke ; Rothen‐Rutishauser, Barbara

In: Advanced Sustainable Systems, 2020, vol. 4, no. 1, p. 1900101

Polydopamine can form black nanoparticles and has recently been gaining attention due to its extraordinary heating properties upon excitation with light. Herein, polydopamine hybrid nanoparticles are synthesized in different sizes and subsequently added to a solar fluid to analyze heating ability. The solar fluids with the differently sized hybrid polydopamine particles are compared to a...

Université de Fribourg

A literal elytral rainbow: tunable structural colors using single diamond biophotonic crystals in Pachyrrhynchus congestus weevils

Wilts, Bodo D. ; Saranathan, Vinodkumar

In: Small, 2018, vol. 14, no. 46, p. 1802328

The brilliant colors of many insects arise from the interference of incident light with complex nanostructured biomaterials that are present in their cuticle. Here, the rainbow‐colored spots on the elytra of a snout weevil, Pachyrrhynchus congestus pavonius (Coleoptera: Curculionidae), are investigated using synchrotron small‐angle X‐ray scattering, scanning electron microscopy,...

Université de Fribourg

Thin-film structural coloration from simple fused scales in moths

Kilchoer, Cédric ; Steiner, Ullrich ; Wilts, Bodo D.

In: Interface Focus, 2019, vol. 9, no. 1, p. 20180044

The metallic colouration of insects often originates from diverse nanostructures ranging from simple thin films to complex three-dimensional photonic crystals. In Lepidoptera, structural colouration is widely present and seems to be abundant in extant species. However, even some basal moths exhibit metallic colouration. Here, we have investigated the origin of the vivid metallic colours of...

Université de Fribourg

When black and white make green: the surprising interplay of structure and pigments

Sai, Tianqi ; Wilts, Bodo D. ; Sicher, Alba ; Steiner, Ullrich ; Scheffold, Frank ; Dufresne, Eric R.

In: CHIMIA International Journal for Chemistry, 2019, vol. 73, no. 1, p. 47–50

The natural world is teeming with color, which originates either from the wavelength- dependent absorp- tion of light by pigments or from scattering from nanoscale structures, or both. While the latter ' structural color ' has been a topic of intense study in recent years, the most vibrant colors in nature involve contributions from both structure and pigment. The study of structure–pigment...

Université de Fribourg

Circularly polarized reflection from the scarab beetle Chalcothea smaragdina: light scattering by a dual photonic structure

McDonald, Luke T. ; Finlayson, Ewan D. ; Wilts, Bodo D. ; Vukusic, Pete

In: Interface Focus, 2017, vol. 7, no. 4, p. 20160129

Helicoidal architectures comprising various polysaccharides, such as chitin and cellulose, have been reported in biological systems. In some cases, these architectures exhibit stunning optical properties analogous to ordered cholesteric liquid crystal phases. In this work, we characterize the circularly polarized reflectance and optical scattering from the cuticle of the beetle Chalcothea...