Si Radial p-i-n Junction Photovoltaic Arrays with Built-In Light Concentrators.

High-performance photovoltaic (PV) devices require strong light absorption, low reflection and efficient photogenerated carrier collection for high quantum efficiency. Previous optical studies of vertical wires arrays have revealed that extremely efficient light absorption in the visible wavelengths is achievable. Photovoltaic studies have further advanced the wire approach by employing radial p-n junction architectures to achieve more efficient carrier collection.

Measuring changes in activity patterns during a norovirus epidemic at a retirement community.

Ubiquitous and unobtrusive in-home monitoring has the potential to detect physical and mental decline earlier and with higher precision than current clinical methods. However, given that this field is in its infancy, the specific metrics through which these changes are detected are not well defined. The work presented here offers room-transitions, the act of physically moving from one area of a home to another, as a quantifiable measure for total daily activity that can be inferred from a network of passive infrared sensors.

Effects of peripheral and axial substitutions on electronic transitions of tin naphthalocyanines.

Tin naphthalocyanine molecules display strong absorption in the infrared region (IR), making them ideal as components of organic photodiodes and solar cells. We use density functional theory and time-dependent density functional theory (TD-DFT) at the B3LYP level to study the influence of axial and peripheral ligands on the absorption wavelength of tin naphthalocyanines. We find that TD-DFT is successful at reproducing the experimental absorption spectra of free base naphthalocyanine and tin naphthalocyanine molecules and can be used as a reliable tool to predict absorption spectra of substituted naphthalocyanines.

Asteroids and andesites.

The production of terrestrial andesites in subduction zones is well established. Day et al. describe two examples of meteorites (GRA 06128 and GRA 06129) that they claim to represent "an entirely new mode of generation of andesite crust compositions" on asteroids; this suggestion has wide implications for the generation of andesitic planetary crusts in general.