University of Warsaw

About: University of Warsaw is a education organization based out in Warsaw, Poland. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 20832 authors who have published 56617 publications receiving 1185084 citations. The organization is also known as: Uniwersytet Warszawski & Warsaw University.

Planck intermediate results - XXX. The angular power spectrum of polarized dust emission at intermediate and high Galactic latitudes

Abstract: The polarized thermal emission from diffuse Galactic dust is the main foreground present in measurements of the polarization of the cosmic microwave background (CMB) at frequencies above 100 GHz. In this paper we exploit the uniqueness of the Planck HFI polarization data from 100 to 353 GHz to measure the polarized dust angular power spectra C_l^(EE) and C_l^(BB) over the multipole range 40

Highly efficient water splitting by a dual-absorber tandem cell

Abstract: Photoelectrochemical water-splitting devices, which use solar energy to convert water into hydrogen and oxygen, have been investigated for decades. Multijunction designs are most efficient, as they can absorb enough solar energy and provide sufficient free energy for water cleavage. However, a balance exists between device complexity, cost and efficiency. Water splitters fabricated using triple-junction amorphous silicon1,2 or III–V3 semiconductors have demonstrated reasonable efficiencies, but at high cost and high device complexity. Simpler approaches using oxide-based semiconductors in a dual-absorber tandem approach4,5 have reported solar-to-hydrogen (STH) conversion efficiencies only up to 0.3% (ref. 4). Here, we present a device based on an oxide photoanode and a dye-sensitized solar cell, which performs unassisted water splitting with an efficiency of up to 3.1% STH. The design relies on carefully selected redox mediators for the dye-sensitized solar cell6,7 and surface passivation techniques8 and catalysts9 for the oxide-based photoanodes. A photoelectrochemical cell made from combining a dye sensitized solar cell with a semiconductor-oxide photoanode is demonstrated to perform water splitting with an efficiency of up to 3.1%. As the scheme uses relatively inexpensive materials and fabrication techniques it could provide a cost effective approach to hydrogen production.