A metal-organic framework could serve as a replacement for the semiconductor silicon in the future. © MPI-P

Scientists at the Max Planck Institute for Polymer Research (MPI-P) in Mainz (Germany) together with scientists from Dresden, Leipzig, Sofia (Bulgaria) and Madrid (Spain) have now developed and characterized a novel, metal-organic material which displays electrical properties mimicking those of highly crystalline silicon. The material which can easily be fabricated at room temperature could serve as a replacement for expensive conventional inorganic materials used in optoelectronics.

The novel topological insulator built in the Würzburg Institute of Physics: a controllable flow of hybrid optoelectronic particles (red) travels along its edges. (Picture: Karol Winkler)

For the first time, physicists have built a unique topological insulator in which optical and electronic excitations hybridize and flow together. They report their discovery in "Nature". Topological insulators are materials with very special properties. They conduct electricity or light particles on their surface or edges only but not on the inside. This unusual behaviour could eventually lead to technical innovations which is why topological insulators have been the subject of intense global research for several years.

Hardmetal sample with complex geometry on FFF standard printer Hage3D 140 L, in which larger components can be perspectively printed as well. © Fraunhofer IKTS

Extremely hard tools are required in forming technology, metal-cutting and process engineering. They are conventionally made by powder pressing. Although this achieves a high degree of hardness, it is often necessary to carry out a complex and therefore expensive post-processing. Additive manufacturing enables complex geometries, but has been limited in terms of hardness and component size so far. Researchers at the Fraunhofer IKTS in Dresden have now adapted the 3D printing process Fused Filament Fabrication for hardmetals. The development meets all requirements for the first time.

The engineers coated a glass plate with a particularly smooth and conductive polymer layer of “Poly(Kx[Ni-itto])” by rotation coating (“spin coating”). Fraunhofer IWS Dresden

Thin organic layers provide machines and equipment with new functions. They enable, for example, tiny energy recuperators. In future, these will be installed on pipes or other surfaces in order to convert waste heat into electricity. The experts at the Fraunhofer Institute for Material and Beam Technology IWS Dresden use ink based on conductive polymers for this purpose.