Kinetic Stabilization of the Sol–Gel State in Perovskites is the Key to Fabricate High‐Efficiency Solar Cells
Well-controlled solution processing is the key to achieving highly efficient and stable perovskite solar cells. Clear guidelines are necessary for designing formulations enabling device production with ease and with high reproducibility. Amassian research group at NCSU has found out that a systematic widening of the anti‐solvent processing window for the fabrication of high‐quality films and efficient solar cells can be achieved through halide and cation engineering. The research ascertains that processing window widens from seconds, in the case of single cation/halide systems (e.g., MAPbI3, FAPbI3, and FAPbBr3), to several minutes for mixed systems. This processing window is closely related to the crystallization of the disordered sol–gel and to the number of crystalline byproducts as revealed in in-situ X‐ray diffraction studies. This research work, which appears in Advanced Materials, has also shown that anti‐solvent dripping promotes the desired perovskite phase with the careful formulation. The results have a crucial impact on the further development of perovskite solar cells.
Figure: a–d) In situ 2D GIWAXS intensity maps plot of various films; e–h) power conversion efficiency statistical distribution of solar cells with varied dripping time; i–l) SEM images of the perovskite films with varied dripping time.
