20.8 Slot Die Coated MAPbI 3 Perovskite Solar Cells by Optimal DMSO Content and Age of 2 ME Based Precursor Inks

Solar cells incorporating metal halide perovskite MHP semiconductors are continuing to break efficiency records for solution processed solar cell devices. Scaling MHP based devices to larger area prototypes requires the development and optimization of scalable process technology and ink formulations that enable reproducible coating results. It is demonstrated that the power conversion efficiency PCE of small area methylammonium lead iodide MAPbI3 devices, slot die coated from a 2 methoxy ethanol 2 ME based ink with dimethyl sulfoxide DMSO used as an additive depends on the amount of DMSO and age of the ink formulation. When adding 12 mol of DMSO, small area devices of high performance 20.8 are achieved. The effect of DMSO content and age on the thin film morphology and device performance through in situ X ray diffraction and small angle X ray scattering experiments is rationalized. Adding a limited amount of DMSO prevents the formation of a crystalline intermediate phase related to MAPbI3 and 2 ME MAPbI3 2 ME and induces the formation of the MAPbI3 perovskite phase. Higher DMSO content leads to the precipitation of the DMSO 2MA2Pb3I8 intermediate phase that negatively affects the thin film morphology. These results demonstrate that rational insights into the ink composition and process control are critical to enable reproducible large scale manufacturing of MHP based devices for commercial application