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For use in windows, solar cells need to absorb enough light to produce sufficient energy, but let enough pass through to be transparent. Organic photovoltaic materials can absorb infrared light and pass visible light, but they have very low efficiencies. Inorganic semiconductors, such as amorphous silicon, absorb strongly in the visible part of the spectrum, so the films have to be very thin to be transparent, thus decreasing the amount of photons they capture. They also tend to give windows a brownish or reddish tint, which architects dislike. The Oxford team, led by physicist Henry J. Snaith, made their solar...

Linus Torvalds once led a ragtag band of software geeks. Not anymore. Here's an inside look at how the unusual Linux business model increasingly threatens Microsoft Five years ago, Linus Torvalds faced a mutiny. The reclusive Finn had taken the lead in creating the Linux computer operating system, with help from thousands of volunteer programmers, and the open-source software had become wildly popular for running Web sites during the dot-com boom. But just as Linux was taking off, some programmers rebelled. Torvalds' insistence on manually reviewing everything that went into the software was creating a logjam, they warned. Unless he...