Manipulating Perovskite Crystallization and Healing Buried Interfaces via a Versatile Organic Additive for High-Performance Cesium Halide Perovskite Solar Cells

Numerous perovskite defects and inferior buried interfaces considerably limit the stability and efficiency of inorganic cesium halide perovskite solar cells. Here, an organic additive, N -(2-acetamido)-2-aminoethanesulfonic acid (AAESA), is added into a CsPbIBr 2 precursor for simultaneously ameliorating CsPbIBr 2 perovskite quality through manipulating perovskite crystallization and healing the buried interface through forming an AAESA interlayer at the interface. It is found that the interaction of the AAESA molecule with the CsPbIBr 2 precursor component slows the perovskite crystallization rate, which results in the fabrication of CsPbIBr 2 perovskite film with improved crystal quality and enlarged crystal grains. Meanwhile, AAESA molecules are pushed downward during the perovskite crystallization process and form an interlayer at the buried CsPbIBr 2 perovskite/TiO 2 layer interface, which heals the buried interface and accelerates the interface charge transfer. The resulting planar CsPbIBr 2 perovskite solar cell with a carbon electrode demonstrates an efficiency of 10.89%. Moreover, the cell without encapsulation preserves ∼90% of the original efficiency after 960 h under ambient conditions, indicating a high stability.