Berkeley Lab researchers have discovered why a promising technique for making quantum dots and nanorods has so far been a disappointment. Better still, they’ve also discovered how to correct the problem.

At Berkeley Lab’s Advanced Light Source, scientists seeking ways to use cement more efficiently and reduce the carbon emissions associated with its manufacture have revealed new properties of the mineral tobermorite. Using x-ray-diffraction to probe the crystalline structure of Portland cement’s most important component, they squeezed the mineral in a diamond anvil cell to pressures equivalent to 100 miles deep in the Earth.

Berkeley Lab researchers at the Molecular Foundry have discovered a universal technique for stripping nanocrystals of tether-like molecules that pose as obstacles for their integration into devices. These findings could provide scientists with a clean slate for developing new nanocrystal-based technologies for energy storage, photovoltaics, smart windows, solar fuels and light-emitting diodes.

Berkeley Lab researchers may have opened the door to a simpler approach for the fabrication of plasmonic materials – one of the hottest new fields in high tech – by inducing polyhedral-shaped silver nanocrystals to self-assemble into three-dimensional millimeter-sized supercrystals of the highest possible density.

Berkeley Lab researchers at the Molecular Foundry have shed light on the role of temperature in controlling a fabrication technique for drawing chemical surface patterns as small as 20 nanometers. This technique could provide an inexpensive, fast route to growing and patterning a wide variety of materials on surfaces to build electrical circuits and chemical sensors, or study how pharmaceuticals bind to proteins and viruses.

Theoretical research by Berkeley Lab scientists has led to record-breaking efficiencies in solar cells. The research showed that, contrary to conventional scientific wisdom, the key to solar cell efficiency is not absorbing more photons but emitting more photons.

Berkeley Lab researchers at the Molecular Foundry like their solutions shaken, not stirred. In this way they have been able to engineer two-dimensional, biomimetic nanosheets with atomic precision for a wide range of applications, including the creation of platforms for sensing molecules, and membranes for filtration. To enable this self-assembly of 2D nanosheets they have developed a programmable device to rock the vial of solutions. They call it a “SheetRocker.”

President Obama has named two Berkeley Lab researchers, Christian Bauer of the Physics Division and Feng Wang of the Materials Sciences Division, among the 13 Department of Energy scientists who are recipients of the 2011 Presidential Early Career Award for Scientists and Engineers. This year’s 94 winners were nominated by 14 government agencies. In addition to a plaque and citation, the awards continue research funding for up to five years and are considered the U.S. government’s highest honor to young scientists.

Some ferroelectric materials can develop extremely high voltages when light falls on them, which might greatly improve solar cells if scientists could figure out how they do it. Researchers at Lawrence Berkeley National Laboratory have solved the mystery for one ferroelectric, bismuth ferrite, revealing a principle that should apply to other materials too. The secret is an electronic “bucket brigade” that passes electrons stepwise from one electrically polarized region to the next.

Invisible terahertz light can detect explosives, image drug structures, and pinpoint skin cancer, but practical tools for using it are scarce. Now Berkeley Lab scientists have demonstrated a device made of graphene microribbons that strongly responds to terahertz light by exciting the collective electron oscillations known as plasmons. The device can be tuned with exquisite precision by varying the width of the graphene ribbons and controlling electron density.