(Funded by the National Science Foundation and the U.S. Department of Energy)
Researchers from Florida State University, the University of California Santa Barbara, Tsinghua University in China, Leipzig University in Germany, and Stuttgart University in Germany have identified, for the first time, the existence of local collective excitations of #electrons, called #plasmons, in a #Kagome metal – a class of materials whose atomic structure follows a hexagonal pattern that looks like a traditional Japanese basket weave – and found that the wavelength of those plasmons depends upon the thickness of the metal. The researchers also found that changing the frequency of a #laser shining at the metal caused the plasmons to spread through the material rather than staying confined to the surface. “[O]ur research reveals how electron interactions can create these unique waves at the nanoscale,” said Guangxin Ni, the scientist who led this study. “This breakthrough is key for advancing technologies in nano-optics and nano-photonics.”

(Funded by the National Science Foundation and the U.S. Department of Defense)
Putting 50 billion transistors into a microchip the size of a fingernail is a feat that requires manufacturing methods of nanometer-level precision. The process relies heavily on solvents that carry and deposit materials in each layer – solvents that can be difficult to handle and toxic to the environment. Now, researchers from Tufts University and Istituto Italiano di Tecnologia in Milan, Italy, have developed a nanomanufacturing approach that uses water as the primary solvent, making it more environmentally compatible and opening the door to the development of devices that combine inorganic and biological materials.

(Funded by the National Science Foundation and the U.S. Department of Defense)
Researchers from the University of California San Diego have developed an innovative approach to multispectral photodetection by alternating layers of graphene and colloidal quantum dots. By carefully engineering the material stack, the researchers created photodetectors sensitive to different wavelength bands without additional optical components. The key innovation lies in using graphene monolayers as independent charge collectors at different depths within a quantum dot absorber layer.

(Funded by the National Science Foundation and the U.S. Department of Energy)
Researchers from Penn State and the National Institute for Materials Science in Japan have created a switch that turns on and off the presence of “kink states” – electrical conduction pathways at the edge of semiconducting materials. By controlling the formation of the kink states, researchers can regulate the flow of electrons in a quantum system. Kink states exist in a quantum device built with a bilayer graphene, which comprises two layers of atomically thin carbon stacked together, in such a way that the atoms in one layer are misaligned to the atoms in the other. “The amazing thing about our devices is that we can make electrons moving in opposite directions not collide with one another … even though they share the same pathways,” said Ke Huang, one of the scientists involved in this study.

(Funded by the National Science Foundation)
Researchers from North Carolina State University, the Leibniz Institute of Polymer Research Dresden in Germany, Technische Universität Dresden in Germany, and Otto von Guericke University Magdeburg in Germany have embedded gold nanorods in hydrogels that can be processed through 3D printing to create structures that contract when exposed to light and expand when the light is removed. When the hydrogel structures are exposed to light, the embedded gold nanorods convert that light into heat. This causes the polymers in the hydrogel to contract, pushing water out of the hydrogel and shrinking the structure. When the light is removed, the polymers cool down and begin absorbing water again, which expands the hydrogel structure to its original dimensions. Because this expansion and contraction can be performed repeatedly, the 3D-printed structures can serve as remotely controlled actuators.