Perovskites, calcium titanium oxide minerals composed of calcium titanate, with the chemical formula CaTiO, are found in relative abundance throughout the world and have characteristics that make them a plausible candidate for use in solar cells. Initially showing good efficiency at small scales, perovskite solar cells were potentially less expensive to produce than conventional silicon-based units, and could be more efficient, especially as single-layer silicon cells reach their theoretical limit of 30-percent efficiency. Perovskite cells could be configured to respond to different wavelengths of light, stacked on one another, and still be thinner than conventional solar cells. Part of the attraction of perovskites cells has been their rapid increase in efficiency, nearly equaling the best silicon cells in about six years, as opposed to the 35 years needed for silicon cells to increase from 16 percent efficiency to a little over 25. Some factors get in the way, one being that perovskites react badly with moisture. Thus, their life spans are much shorter than the more …
Traversing Australia on Sunshine
Australia supplies 3,000 kilometers (1,860 miles) of smooth road and abundant sunshine every year for the Bridgestone World Solar Challenge that bisects the country north to south. Growing in numbers annually, this year’s five-day race drew 47 teams from 25 countries, with two teams from the Netherlands, one from the University of Michigan in the United States and one from Tokai University in Japan trading the lead almost daily and battling it out for the first four places in the Challenger Class with daily consistency. University of Delft students had their second win in two years, while rivals from the University of Twente (the Netherlands) achieved a very strong second place overall. The University of Michigan’s team was a consistent third-place contender, only to be bested at the end by Tokai’s final sprint. Even at 3,000 kilometers, Nuon and Solar Team Twente were just over two and a half minutes apart. Delft’s car traveled the 3002 kilometers in 37 hours, 56 …