Photovoltaic cells offer high visible light transparency

Fitting such cells to a building’s windows could potentially enable the entire surface area of the windows to generate electricity.

Today, from half to two thirds of the cost of a traditional, thin-film solar-power system comes from installation costs and up to half of the cost of the panels themselves is for the glass and structural parts.

But the transparent photovoltaic system, developed by Vladimir Bulović, professor of electrical engineering in MIT’s Department of Electrical Engineering and Computer Science with Richard Lunt, a postdoctoral researcher, could eliminate many of those costs.

Previous attempts to create transparent solar cells have either had extremely low efficiency (less than one per cent of incoming solar radiation is converted to electricity), or have blocked too much light to be practical for use in windows.

But the MIT researchers were able to find a specific chemical formulation for their cells that, when combined with partially infrared-reflective coatings, gives both high visible light transparency and much better efficiency than earlier versions — comparable to that of non-transparent organic photovoltaic cells.