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A D V A N C E D M A T E R I A L S & P R O C E S S E S | M A Y / J U N E 2 0 1 9 1 1 2Dmaterial scanned using the nanoARPES x-ray technique. Courtesy of Berkeley Lab. examines a polymer doped with fluo- rescent molecules that emit light of one wavelength when they are illuminated with light of another wavelength. An image of the emitted light reveals not only a molecule’s location, but also its orientation. The scientists now plan to improve resolution by a factor of five— allowing them to image areas as small as a few nanometers. nist.gov. UNDERSTANDING DEFECTS IN 2D MATERIALS A new understanding of nanoscale defects in 2D materials could play an important role in developing better solar technology. Scientists from the DOE’s Berkeley Lab, Calif., learned how these defects can enhance the proper- ties of an ultrathin 2D material. They combined a range of techniques to hone in on nanoscale defects formed in the manufacture of tiny flakes of tung- sten disulfide. WS 2 and other 2D materials could serve as high-efficiency computer tran- sistors and could also be used in ul- trathin solar cells, LED lighting, and quantum computers. In addition, these materials could be used in new forms of memory storage and data transfer, such as spintronics. The latest results mark the first comprehensive study at the lab’s Advanced Light Source (ALS) involving a technique called nanoARPES, which researchers use to probe the 2D samples with x-rays. The team also used x-ray photoelec- tron spectroscopy to study the chem- ical makeup of a sample, atomic force microscopy to view structural details, and optical spectroscopy to study how light interacts with the electrons. In this research, defects were found to be due to the sample growth process. Future studies will focus on samples with defects that are induced through chemical processing or other treatments. Researchers hope to con- trol the amount and kinds of atoms that are affected, and the locations where defects are concentrated. Such tweaks could be important for processes like catalysis and to explore quantum pro- cesses that rely on the production of individual particles that serve as infor- mation carriers in electronics. lbl.gov.