How to Make over 20% Efficient Perovskite Solar Cells in Regular (n–i–p) and Inverted (p–i–n) Architectures - Saliba, Michael; Correa-Baena, Juan-Pablo; Wolff, Christian M; Stolterfoht, Martin; Phung, Nga; Albrecht, Steve; Neher, Dieter; Abate, Antonio (Chemistry of materials, 2018)