Tag Archives: electronic structure

Researchers Find Simple, Cheap Way to Increase Solar Cell Efficiency

Researchers from North Carolina State University and the Chinese Academy of Sciences have found an easy way to modify the molecular structure of a polymer commonly used in solar cells. Their modification can increase solar cell efficiency by more than 30 percent.

Polymer-based solar cells have two domains, consisting of an electron acceptor and an electron donor material. Excitons are the energy particles created by solar cells when light is absorbed. In order to be harnessed effectively as an energy source, excitons must be able to travel quickly to the interface of the donor and acceptor domains and retain as much of the light’s energy as possible. (more…)

Read More

UCLA chemistry graduate student ready for her Nobel journey

Crystal Valdez selected to meet with 34 laureates at international conference

From the time she was a young girl, Crystal Valdez was fascinated by science. “When I first learned we are composed of cells and that cells are composed of molecules and atoms, I was amazed and wanted to understand how it all works,” the chemistry graduate student recalled.

That curiosity ultimately led her to the laboratory of Anastassia Alexandrova at UCLA, where Valdez has earned a reputation for her research on the design and function of enzymes. (more…)

Read More

Another Advance on the Road to Spintronics

Berkeley Lab Researchers Unlock Ferromagnetic Secrets of Promising Materials

Spintronic technology, in which data is processed on the basis of electron “spin” rather than charge, promises to revolutionize the computing industry with smaller, faster and more energy efficient data storage and processing. Materials drawing a lot of attention for spintronic applications are dilute magnetic semiconductors – normal semiconductors to which a small amount of magnetic atoms is added to make them ferromagnetic. Understanding the source of ferromagnetism in dilute magnetic semiconductors has been a major road-block impeding their further development and use in spintronics. Now a significant step to removing this road-block has been taken.

A multi-institutional collaboration of researchers led by scientists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab), using a new technique called HARPES, for Hard x-ray Angle-Resolved PhotoEmission Spectroscopy, has investigated the bulk electronic structure of the prototypical dilute magnetic semiconductor gallium manganese arsenide. Their findings show that the material’s ferromagnetism arises from both of the two different mechanisms that have been proposed to explain it. (more…)

Read More