Our work in collaboration with Peking University on the effective passivation of several types of vacancy defects in metal halide perovskite for highly stable perovskite solar cells by small anions is published today on Nature Energy. We obtain stable perovskite solar cells, retaining 90% of its original power-conversion efficiency after 1000 hours operation at maximum-power-point. Combining experiments and theory, we demonstrate the small anions are very effective in passivating vacancy defects thanks to its extremely high electronegativity and its unique strong interactions with the perovskite lattices. Details of the research can be found at Nature Energy4, 408–415 (2019) and at press release from TU/e, C&EN (newsletter of the American Chemical Society), NEMO kennislink (the biggest popular science website in the Netherlands) and an interview at dutch Radio BNR wetenschap show (science show).