The latest advances in carbon nanotube–silicon heterojunction solar cells are combined with a new doping protocol based on the outstanding electron withdrawing properties and excellent silicon surface passivation ability of sulfonated polytetrafluoroethylene (Nafion). Using this new dopant for carbon nanotube –silicon solar cells, advanced substrate design, and an optimized antireflective texture fast etch with organic base, breakthrough performance is obtained from research grade devices with active areas of 1 and 5 cm2, which yield power conversion efficiencies of 17.2 and 15.5%, respectively.
Featured Application: The implementation of single-shot grating-based imaging within existing X-ray scanners will offer enhanced imaging contrast for weakly absorbing objects and materials with similar absorption cross-sections, profiting from phase and small-angle scattering contrasts. Due to the provided multi-modal information, such techniques can find broad applications in pre-clinical imaging of soft tissues, the determination of composite material structural orientation, and the visualization of formation processes of different natures, etc. To adapt the imaging modality to the intended application and profit from the versatility of those techniques, one requires customized optical elements. Our group has developed novel two-dimensional gratings, optimized for X-ray imaging at energies from 8 keV up to 25 keV, which can be used for orientation-independent inspection of materials within radiography setup.Abstract: Single-shot grating-based phase-contrast imaging techniques offer additional contrast modalities based on the refraction and scattering of X-rays in a robust and versatile configuration. The utilization of a single optical element is possible in such methods, allowing the shortening of the acquisition time and increasing flux efficiency. One of the ways to upgrade single-shot imaging techniques is to utilize customized optical components, such as two-dimensional (2D) X-ray gratings. In this contribution, we present the achievements in the development of 2D gratings with UV lithography and gold electroplating. Absorption gratings represented by periodic free-standing gold pillars with lateral structure sizes from 5 µm to 25 µm and heights from 5 µm to 28 µm have shown a high degree of periodicity and defect-free patterns. Grating performance was tested in a radiographic setup using a self-developed quality assessment algorithm based on the intensity distribution histograms. The algorithm allows the final user to estimate the suitability of a specific grating to be used in a particular setup.
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