Black-silicon Cell Efficiency above 130 Percent

Dean Sigler Announcements, Solar Power, Sustainable Aviation Leave a Comment

Aalto University in Espoo, Finland has announced a seemingly impossible breakthrough – black-silicon solar cells that exceed 100-percent efficiency.  This breaks the Shockley-Queisser limit, previously thought to be an unbreakable barrier to any solar cell generating more than 33.7-percent efficiency for a single p-n junction photovoltaic cell.  The 1,000 Watts of sunlight falling on a square meter of single-junction solar cells could never produce more than 337 Watts to a battery or other receiving mechanism.  William Shockley, a co-winner of the Nobel Prize in Physics for his co-creation of the transistor and Hans-Joachim Queisser defined this limit at Shockley Semiconductor in 1961. In a traditional solid-state semiconductor such as silicon, a solar cell is made from two doped crystals.  One is an n-type semiconductor, which has extra free electrons, …

100 Percent Efficiency? Great! and So What?

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

A particularly brilliant and demanding manager for whom your editor used to work had a “SO WHAT?” stamp with which he would critique our technical papers and proposals.  His point in defacing our papers was not to be snide, but to force us to defend why we included certain facts – interesting though they may be in themselves. Two different and equally brilliant discoveries by University of Cambridge and University of California, Riverside researchers bring the “so what?” stamp to mind.  Even with their breakthroughs, approaching 100-percent efficient solar cells in the first instance, solar cells may not yet be a perfect fit for aircraft propulsion. Each square foot of the earth’s surface receives about 15 Watts of solar energy …

Nanowire Solar Cells Surprise and Excite

Dean Sigler Electric Powerplants, Sustainable Aviation Leave a Comment

Long-time friend of the blog, and occasional corrector of the editor’s attempts at incorporating French into the proceedings, Colin Rush sent this link to a story about photonics in the Christian Science Monitor. “Wires 1/10,000th the diameter of a human hair can absorb more of the sun’s power than previously thought possible, a new study in Nature Photonics suggests,” writes David Unger, an energy correspondent for the Monitor. Unger’s lead paragraphs pushed your editor to look up several related terms and look further into the researchers’ own writing.  “Although still years away from production, nanowire solar cells could push the conversion efficiency of the sun’s energy past the so-called Shockley-Queisser limit, which for decades has served as a fixed ceiling in solar energy research. …