A team of researchers affiliated with institutions in the U.K., China and Australia has developed a cleaning-healing-cleaning method that eliminates ionic defects on the surface of 3-D perovskite films. In their paper published in the journal Nature Electronics, the group describes their process and how well it works. Huihui Zhu, Ao Liu and Yong-Young Noh with the University of Science and Technology in Korea have published a News & Views piece in the same journal issue outlining the uses for metal halide perovskite semiconductors, factors limiting their use as field-effect transistors, and the work done by the team on this new effort.