Out of Sandia National Laboratories comes a glitter that could change the world of solar power. Tiny, hexagonal solar cells thinner than a human hair could be the fast-track to solar-powered clothing and building-integrated photovoltaic products. The cells are made from silicon, the semiconductor common to rigid, conventional PV panels, but are so tiny they can easily be fixed to flexible substrates.
And here’s the kicker. At just 14 to 20 micrometers thick, MEMS solar cells produce the same amount of energy as a conventional silicon cell with 100 times less silicon.
Eventually, the solar cells are expected to be cheaper and more efficient than current silicon solar cells. To date, cells tested at Sandia National Lab have shown a 14.9% conversion efficiency. Using crystalline silicon and microelectromechanical systems (MEMS) already used in the electronics industry, Sandia researchers created the “microphotovoltaic” cells, which they say proffer several benefits over conventional silicon cells. Not least of these are improved performance, new applications, reduced costs and increased efficiencies.
Furthermore, solar cells fabricated in this fashion and on this scale could have inverters, smart controls and energy storage built in at the chip level. This could lead to major benefits for the building industry and could allow people to become their own power producers, charging electronic devices while walking down the street. Ordinary-looking building materials could have MEMS cells built into them. A roof with integrated panels would not have to worry as much about shading either. The tiny makeup of the cells allows them a high shade tolerance; if some cells in a panel are shaded, the others will continue to produce electricity.
The cells are ideal for both large- and small-scale solar applications due to low manufacturing costs and the versatility of the small-cell approach. They can be printed onto a flexible or rigid substrate and onto any of the wafers in production today.
Taking a page from solar thermal power, concentrators can be placed over each cell to multiply the number of photons hitting it. And the list of potential benefits goes on: their small scale allows for high voltage output, cells and panels can easily be mass-produced using existing technology with even cheaper processes to come, and other possible applications include satellites and remote sensing.
Photo Credit: Sandia