Cellular interfaces with hydrogen-bonded organic semiconductor hierarchical nanocrystals.

Successful formation of electronic interfaces between living cells and semiconductors hinges on being able to obtain an extremely close and high surface-area contact, which preserves both cell viability and semiconductor performance. To accomplish this, we introduce organic semiconductor assemblies consisting of a hierarchical arrangement of nanocrystals. These are synthesised via a colloidal chemical route that transforms the nontoxic commercial pigment quinacridone into various biomimetic three-dimensional arrangements of nanocrystals.

A generic concept to overcome bandgap limitations for designing highly efficient multi-junction photovoltaic cells.

The multi-junction concept is the most relevant approach to overcome the Shockley-Queisser limit for single-junction photovoltaic cells. The record efficiencies of several types of solar technologies are held by series-connected tandem configurations. However, the stringent current-matching criterion presents primarily a material challenge and permanently requires developing and processing novel semiconductors with desired bandgaps and thicknesses.

Measurement of the enhanced evanescent fields of integrated waveguides for optical near-field sensing.

The sensitivity of an integrated optical sensing device can be enhanced by coating it with a high refractive index layer, while both incoupled intensity and spatial resolution are maintained. The potential for enhanced sensing is demonstrated using titanium indiffused waveguiding structures in LiNbO(3) coated with a TiO(2) film. To the best of our knowledge, it could be measured for the first time that the outcoupled intensity at the surface was enhanced by a factor of 12-15 while keeping the penetration depth of the evanescent field constant of the order of only a few tens of nanometers.