Photovoltaic Effect of WS2 Nanotube Devices

Characterization of WS2 nanotube devices image

The bulk photovoltaic effect (BPVE) in WS2 nanotube devices is quite stable in terms of quality and quantity. The large decrease in the short-circuit current (Isc) with decreasing temperature cannot be explained simply by a decrease in the absorption coefficient, because the band gap is blue-shifted with decreasing temperature. Light with a wavelength of 632.8 nm (1.96 eV) almost resonates with the A-exciton of WS2 (a specific bonded state of an electron and a hole) and therefore produces the strongest signal.

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Photovoltaic Effect of WS2 Bilayer Device Under Laser Illumination

Overview of the bulk photovoltaic effect in various materials image

The short-circuit current (Isc) under laser illumination is an important parameter for the evaluation of photovoltaic effects. We measured this current for WS2 bilayer device with different crystal symmetries. For each device, we scanned the laser spot from one electrode to the other to distinguish the BPVE from the Schottky barrier photovoltaic effect as well as the photothermal effect near the contact.

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Titanium Oxide Tungstate Nanotubes Improve Fuel Cell Performance

Tensile strength of SPEEK and composite membranes image

Titanium oxide tungstate nanotubes could improve fuel cell performance. The chemical oxidative stability of the tungstate-functionalized sulfonated poly ether ether ketone (SPEEK) membranes is one of the key requirements for the durability and performance of the fuel cells, which was estimated using Fenton's reagent method.

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Enhanced Intrinsic Photovoltaic Effect in Tungsten Disulfide Devices

The photovoltaic response obtained with WS2-based devices of different crystal symmetry image

The bulk photovoltaic effect (BPVE) found in tungsten disulfide devices could further enhance energy conversion rates. The BPVE in conventional p-n junctions - where p-type materials (with excess holes) are adjacent to n-type materials (with excess electrons) - generates current through the light-induced generation and separation of electron-hole pairs. This BPVE is particularly important in energy applications, and its efficiency is now approaching its theoretical limit.

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Tungstate Titanium Oxide Nanotubes Improve Ion Exchange in Fuel Cells

XRD patterns of composite membranes and SPEEK image

Ion exchange capacity is a vital property of ionic membranes, and this property is enhanced with the addition of ion-exchange materials. The IEC value of pure SPEEK membranes is 1.9 meq g-1 due to the contribution of sulfonate group (SO3H). increasing the content of tungstate titanium oxide nanotubes (W-TNT) in sulfonated poly ether ether ketone (SPEEK) membranes could improve the fuel cell ion-exchange capacity.

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