Fraunhofer Society

About: Fraunhofer Society is a government organization based out in Munich, Germany. It is known for research contribution in the topics: Laser & Silicon. The organization has 24736 authors who have published 40168 publications receiving 820894 citations.

The 2018 GaN power electronics roadmap

Abstract: Gallium nitride (GaN) is a compound semiconductor that has tremendous potential to facilitate economic growth in a semiconductor industry that is silicon-based and currently faced with diminishing returns of performance versus cost of investment. At a material level, its high electric field strength and electron mobility have already shown tremendous potential for high frequency communications and photonic applications. Advances in growth on commercially viable large area substrates are now at the point where power conversion applications of GaN are at the cusp of commercialisation. The future for building on the work described here in ways driven by specific challenges emerging from entirely new markets and applications is very exciting. This collection of GaN technology developments is therefore not itself a road map but a valuable collection of global state-of-the-art GaN research that will inform the next phase of the technology as market driven requirements evolve. First generation production devices are igniting large new markets and applications that can only be achieved using the advantages of higher speed, low specific resistivity and low saturation switching transistors. Major investments are being made by industrial companies in a wide variety of markets exploring the use of the technology in new circuit topologies, packaging solutions and system architectures that are required to achieve and optimise the system advantages offered by GaN transistors. It is this momentum that will drive priorities for the next stages of device research gathered here.

Solar cell efficiency tables (version 37)

Abstract: Consolidated tables showing an extensive listing of the highest independently confirmed efficiencies for solar cells andmodulesarepresented.GuidelinesforinclusionofresultsintothesetablesareoutlinedandnewentriessinceJune2010arereviewed. Copyright # 2010 John Wiley & Sons, Ltd. KEYWORDSsolar cell efficiency; photovoltaic efficiency; energy conversion efficiency*CorrespondenceMartin A. Green, ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney 2052, Australia.E-mail: m.green@unsw.edu.auReceived 12 October 2010 1. INTRODUCTION Since January 1993, ‘Progress in Photovoltaics’ haspublished six monthly listings of the highest confirmedefficiencies for a range of photovoltaic cell and moduletechnologies [1–3]. By providing guidelines for theinclusion of results into these tables, this not only providesan authoritative summary of the current state of the art butalso encourages researchers to seek independent confir-mation of results and to report results on a standardisedbasis. In a recent version of these tables (Version 33) [2],results were updated to the new internationally acceptedreferencespectrum(IEC60904–3,Ed.2,2008),wherethiswas possible.Themostimportantcriterionforinclusionofresultsintothe tables is that they must have been measured by arecognised test centre listed elsewhere [1]. A distinction ismade between three different eligible areas: total area;aperture area and designated illumination area [1]. ‘Activearea’ efficiencies are not included. There are also certainminimum values of the area sought for the different devicetypes (above 0.05cm

Efficient hydrogen production on MoNi 4 electrocatalysts with fast water dissociation kinetics

Abstract: Various platinum-free electrocatalysts have been explored for hydrogen evolution reaction in acidic solutions. However, in economical water-alkali electrolysers, sluggish water dissociation kinetics (Volmer step) on platinum-free electrocatalysts results in poor hydrogen-production activities. Here we report a MoNi4 electrocatalyst supported by MoO2 cuboids on nickel foam (MoNi4/MoO2@Ni), which is constructed by controlling the outward diffusion of nickel atoms on annealing precursor NiMoO4 cuboids on nickel foam. Experimental and theoretical results confirm that a rapid Tafel-step-decided hydrogen evolution proceeds on MoNi4 electrocatalyst. As a result, the MoNi4 electrocatalyst exhibits zero onset overpotential, an overpotential of 15 mV at 10 mA cm-2 and a low Tafel slope of 30 mV per decade in 1 M potassium hydroxide electrolyte, which are comparable to the results for platinum and superior to those for state-of-the-art platinum-free electrocatalysts. Benefiting from its scalable preparation and stability, the MoNi4 electrocatalyst is promising for practical water-alkali electrolysers.