Uber-efficient solar cells from nano

UC DAVIS (US) — A new approach to solar power using nanoparticles aims to increase efficiency by generating several electrons from a single proton, instead of the “one in, one out” principle that conventional solar cells operate on.

Researchers believe that by constructing solar cells from germanium, silicon, and other materials, a solar cell’s efficiency—currently capped by a theoretical maximum of 31 percent—could be raised to a maximum efficiency of between 42 and 65 percent.

Conventional solar cells all operate on the same principle of “one photon in, one electron out,” says Gergely Zimanyi, professor of physics at University of California, Davis.

In other words, one particle of light, or photon, hits the solar cell and generates one electron to produce an electrical current.

The one-photon-in/multiple-electrons-out paradigm has been demonstrated at the Los Alamos National Laboratory—but the Los Alamos group did not build a functioning solar cell based on this paradigm.

Scientists from UC Davis, in collaboration with researchers at University of California Santa Cruz, will work to construct a fully functioning and well-optimized solar cell from germanium and silicon nanoparticles, says Zimanyi.

A prototype cell has been already constructed and exhibited an efficiency of about 8 percent, which Zimanyi describes as a very encouraging result given the limited resources going into its construction.

The project was recently awarded $1.5 million over three years from the National Science Foundation. The interdisciplinary nature of the team was crucial to getting the proposal funded, Zimanyi says.

“NSF asked for a collaborative effort between materials sciences, chemistry, and mathematical sciences.”

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