PORTLAND, Ore. Thin-film solar cells that could boost conversion efficiency by 50 percent while cutting materials costs by using less silicon will be reported this week by Massachusetts Institute of Technology researchers at the annual meeting of the Materials Research Society in Boston.
Conventional solar cells use thick, expensive silicon substrates. The MIT researchers said they ran extensive computer simulations and laboratory experiments on 2-micron silicon films that utilize new materials for both front and back coatings. As a result, light is trapped inside the cells' silicon layer, permitting the thin-film to extract as much as 50 percent more energy per photon.
Thin films are being explored extensively as a low-cost alternative to conventional solar cells. Most researchers have achieved dismal thin-film efficiencies compared to single-crystal silicon substrates. The MIT team will report that they combined anti-reflective front coatings with special reflective diffraction gratings as back coatings. As a result, they said thin-film efficiency could rival the cost of today's grid electricity.
The researchers estimate that it will take three years to produce commercial solar cells using MIT's anti-reflective front coatings and reflective back-coated diffraction gratings. MIT's Deshpande Center for Technology Innovationhas recommended placing the thin-film technology on the fast track for licensing to commercial solar cell makers.
Along with the National Science Foundation and the Army Research Office, funding for the research was provided by MIT's Thomas Lord Chair in Materials Science and Engineering.