Strategies are presented for achieving, simultaneously, both large areal coverage and high stretchability by using elastomeric substrates with surface relief in geometries that confine strains at the locations of the interconnections, and away from the devices. The studies involve a combination of theory and experiment to reveal the essential mechanics, and include demonstrations of the ideas in stretchable solar modules that use ultrathin, single junction GaAs solar cells.
A type of compact (∼cm2) high voltage photovoltaic module that utilizes large collections of ultrathin (∼15 μm), small (∼45 μm wide, ∼1 mm long) silicon solar cells was fabricated and characterized. Integration on thin sheets of plastic yielded flexible modules with per-cell efficiencies of ∼8%, voltage outputs >200 V, and maximum power outputs >1.5 mW.
In our work, the new stereolithography technology has been used to construct 3D shark skin teeth with both high resolution and high throughput. In this way complex structures more closely mimicking real shark skin textures have been fabricated (Figure 3-4). Cylinder pipe (at the same size) with and without interior shark skin textures were printed and used to study the effects of the texture in pipe flow. The pressure gradient across shark skin pipe section are measured by existing wet-wet differential pressure transducers. Then this pressure drop measurement can be translated into a friction coefficient by using standard Darcy-Weisbach law. A schematic of the pressure drop measurement setup is shown in Figure 5 and future detailed data analysis will be presented.
Abstract Catalytic interface of semiconductor photoelectrodes is critical for high-performance photoelectrochemical solar water splitting because of its multiple roles in light absorption, electrocatalysis, and corrosion protection. Nevertheless, simultaneously optimizing each of these processes represents a materials conundrum owing to conflicting requirements of materials attributes at the electrode surface. Here we show an approach that can circumvent these challenges by collaboratively exploiting corrosion-resistant surface stoichiometry and structurally-tailored reactive interface. Nanoporous, density-graded surface of ‘black’ gallium indium phosphide (GaInP 2 ), when combined with ammonium-sulfide-based surface passivation, effectively reduces reflection and surface recombination of photogenerated carriers for high efficiency photocatalysis in the hydrogen evolution half-reaction, but also augments electrochemical durability with lifetime over 124 h via strongly suppressed kinetics of corrosion. Such synergistic control of stoichiometry and structure at the reactive interface provides a practical pathway to concurrently enhance efficiency and durability of semiconductor photoelectrodes without solely relying on the development of new protective materials.
Vertically aligned nanorod arrays of CdSe and Zn doped CdSe films were grown on FTO coated glass substrate by using cathodic electro deposition method. The composition, crystal structure, surface morphology and optical properties of the as-grown pure CdSe and Zn doped CdSe nanotubular films were examined by using energy dispersive spectroscopy, x-ray diffractometer, field emission scanning electron microscope, UV-Vis-IR spectrophotometer and photoluminescence techniques, respectively. XRD study showed the hexagonal crystal structure without any precipitates related to Zn. SEM images clearly showed end capped vertically aligned nanorods arranged closely. The optical transmittance spectra were recorded within the range of 300-1000 nm. The band gap energy was found to vary between 1.94 and 1.98 eV due to the incorporation of Zn. PL spectra showed a narrow near band gap emission at 1.81 and 1.94 eV for CdSe and Zn doped CdSe nanorod arrays.
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