Yale E360 has a post on research into transparent solar cells - Transparent Solar Cells Can Turn Windows into Solar Panels.
Researchers at the Massachusetts Institute of Technology (MIT) say they have created a new class of transparent photovoltaic cells that can turn windows into solar panels.
Richard Lunt, a researcher at MIT’s Research Laboratory of Electronics, says the new photovoltaic cells have the potential to turn skyscrapers into enormous solar collectors that could supply much of the electricity needed in modern office buildings. Previous attempts to make transparent solar cells have either failed to achieve high efficiency or blocked too much light. But Lunt and his colleagues say the new transparent cells are built to absorb only the near-infrared spectrum and have the potential to transform light to electricity at relatively high efficiency.
The biggest challenge, said Lunt, is creating photovoltaic cells that would last as long as the windows themselves, since the best way to use the cells would be to package them in the middle of double-pane windows. But Lunt and his colleagues said that the solar cell longevity problem is a basic engineering challenge that can probably be solved within a decade.