Intense light shining on a material used in experimental solar cells can improve its performance.

Perovskite films promise to increase the efficiency of solar cells, but imperfections in the material, called traps, limit further gains. A team led by Samuel Stranks of the Massachusetts Institute of Technology in Cambridge found that intense light reduces the density of the traps by tenfold, boosting performance. Chemical imaging revealed that iodine ions migrated away from the illuminated areas, and the authors suggest that this effectively swept the traps away.

The effect fades over time, but the authors hope to devise a method with longer-lasting effects for commercial applications.

Nature Commun. 7, 11683 (2016)