Stanford Synchrotron Radiation Lightsource

A collection of native Australian plant resins sampled over one hundred years ago serves as a time capsule for scientists to study using modern techniques. The well-annotated and well-preserved samples by unknown collectors feature four species important to Aboriginal Australian technology and culture going back tens of thousands of years. A team of scientists employed advanced x-ray spectroscopy to decipher the molecular composition of this unique collection of samples.

Polymorphism is a fascinating natural phenomenon across many areas of materials science – from small molecules in chemistry, to minerals in geology, to drugs in pharmaceutical industry, to solid-state materials in electronics. High-density polymorphs with unique properties, such as a transparent insulating form of sodium (1) are routinely synthesized under compressive strain at very high pressure. In contrast, applying large negative pressure is very difficult, because large tensile strain usually causes materials to rupture.

Scientists exploring the physics of hearing have found an underlying molecular cause for one form of deafness. The team, led by Gerard Wong, Professor of Materials Science and Engineering, of Physics, and of Bioengineering at the University of Illinois at Urbana-Champaign, report their findings in the February 2007 issue of the journal Physical Review Letters.

New evidence is overturning the assumption that the thermal oxide grown on single crystal silicon is completely amorphous. SSRL researchers Anneli Munkholm (now at Lumileds Lighting) and Sean Brennan recently published work in Physical Review Letters showing that there is residual order within the oxide. The thermal oxide film on silicon has been studied extensively for decades because these oxides form the basis of most of the integrated circuits used in modern electronics. The new results have implications for theoretical models of the oxidation process.

Organic solar cells, which use organic polymers or small organic molecules to convert sunlight into a useable form of energy, are a promising new tool for providing inexpensive, environmentally friendly energy. To date organic solar cells have demonstrated comparatively low rates of efficiency, stability and strength.  However, there is much room for improvement before the theoretical efficiency limits are reached.

Organic semiconductors could usher in an era of foldable smart phones, better high-definition television screens and clothing made of materials that can harvest energy from the sun needed to charge your iPod or iPad, but there is one serious drawback: Organic semiconductors, while inexpensive, do not conduct electricity very well.