Fig. 2From: Perovskite Solar Cells Fabricated by Using an Environmental Friendly Aprotic Polar Additive of 1,3-Dimethyl-2-imidazolidinoneSEM images of the PbI2 films (top) and perovskite films (bottom) a, d without DMI, b, e 10% DMI, and c, f 20% DMIBack to article page