Diamine chelates for increased stability in mixed Sn–Pb and all-perovskite tandem solar cells

The stability of perovskite tandem solar cells is an issue. Li et al. show that diamines improve the compositional homogeneity of a low-bandgap perovskite surface and form a low-dimensional barrier that passivates defects, leading to an operational stability of over 1,000 h.