(Funded by the National Science Foundation)
University of California, Irvine scientists have discovered a one-dimensional nanoscale material whose color changes as temperature changes. “We found that we can make really small and sensitive thermometers,” said Maxx Arguilla, one of the scientists involved in this study. Arguilla likened the thermometers to “nano-scale mood rings,” referring to the jewelry that changes color depending on the wearer’s body temperature. But instead of simply taking a qualitative temperature reading, the changes in the color of these materials “can be calibrated and used to optically take temperature readings at the nanoscale,” Arguilla said.

(Funded by the U.S. Department of Defense, the U.S. Department of Energy, and the National Science Foundation)
Physicists from Purdue University, Washington University in St. Louis, and the U.S. Department of Energy’s Sandia National Laboratories have levitated a fluorescent nanodiamond and spun it at incredibly high speeds (up to 1.2 billion times per minute). The fluorescent diamond emitted and scattered multicolor lights in different directions as it rotated. When illuminated by a green laser, the nanodiamond emitted red light, which was used to read out its electron spin states. An additional infrared laser was shone at the levitated nanodiamond to monitor its rotation. Like a disco ball, as the nanodiamond rotated, the direction of the scattered infrared light changed, carrying the rotation information of the nanodiamond.

(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.