Light-Converting Crystals May be the Future of Solar Panels and LEDs

Engineers have taken a closer look at an emerging family of solar-absorbing materials. Now, they've found that these new materials could pave the way for cheaper and more efficient solar panels and LEDs.

The new materials are called perovskites; these materials are particularly good at absorbing visible light, but had never been thoroughly studied in their purest form as perfect, single crystals. That's why the researchers used a new technique to grow large, pure perovskite crystals for study.

The scientists used a combination of laser-based techniques to measure the selected properties of perovskite crystals. More specifically, they tracked down the rapid motion of electrons in the material to determine the diffusion length, which is how far electrons can travel without getting trapped by imperfections in the material. The researchers also studied mobility, which is how fast the electrons can move.

"Our work identifies the bar for the ultimate solar energy-harvesting potential of perovskites," said Riccardo Comin, one of the researchers, in a news release. "With these materials it's been a race to try to get record efficiencies, and our results indicate that progress is slated to continue without slowing down."

What's especially interesting is that this study has implications for green energy and may also enable innovations in lighting. For example, a solar panel made of perovskite crystals could be constructed as a slab of glass. The electrons could travel easily through the crystal to electrical contacts on its underside, where they would be collected in the form of an electric current. It could also work in reverse; the slab could be powered by electricity and then emit the energy as light.

"In future, we will explore the opportunities for stacking together complementary absorbent materials," said Comin. "There are very promising prospects for combining perovskite work and quantum dot work for further boosting the efficiency."

The findings are published in the journal Science.

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