Germanium Nanorod Extinction Spectra: Discrete Dipole Approximation Calculations and Experiment

Optical extinction spectra were measured for dispersions of germanium (Ge) nanorods produced by arrested solution–liquid–solid (SLS) growth using bismuth (Bi) seeds. Peaks in the real (<i>n</i>) and imaginary (<i>k</i>) parts of the complex index of refraction of Ge give rise to an absorbance peak at ∼600 nm, which shifts to slightly longer wavelengths with increased aspect ratio. Discrete dipole approximation calculations of absorption and scattering cross sections reveal that the length-dependent optical properties result from enhanced light trapping and absorption

Optical Properties of Silicon and Germanium Nanowire Fabric

The optical properties of free-standing nonwoven silicon (Si) and germanium (Ge) nanowire fabrics, including diffuse and specular reflectance, diffuse and direct transmittance, and absorptance spectra, were measured using an integrating sphere to account fully for all incident photons. Very thin, 50 μm thick, sheets with ∼90% void volume have extremely high optical densities. They are optically opaque across nearly all wavelengths from ultraviolet to near-infrared, and only minimal light penetrates when photon energies are below the band gap. The high optical density arises from a combination of scattering and absorption due to their high aspect ratio and narrow diameter as well as surface effects due to their very high surface area to volume ratio

Influences of Gold, Binder and Electrolyte on Silicon Nanowire Performance in Li-Ion Batteries

The effects of binder, electrolyte, and presence of gold (Au) seeds on the performance of silicon (Si) nanowire anodes in Lithium (Li)-ion batteries were systematically examined. Large irreversible capacity loss, poor performance at cycle rates of C/5 and faster, and significant capacity fade were observed when excess Au was not removed from the Si nanowires. Battery stability was very poor when poly (vinylidene fluoride) (PVdF) binder and common carbonate electrolytes, ethylene carbonate, dimethyl carbonate, and diethyl carbonate were used. Respectable Li-ion battery performance was obtained with sodium alginate binder and fluoroethylene carbonate (FEC) added to the electrolyte, with capacities up to 2000 mA h g^–1 after the first 100 cycles

Colloidal Tin–Germanium Nanorods and Their Li-Ion Storage Properties

ISSN:1936-0851ISSN:1936-086