20.8% Slot-Die Coated MAPbI3 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 (MAPbI(3)) 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 MAPbI(3) and 2-ME (MAPbI(3)-2-ME) and induces the formation of the MAPbI(3) perovskite phase. Higher DMSO content leads to the precipitation of the (DMSO)(2)MA(2)Pb(3)I(8) 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 applications.

Automated summary

Efficiency records for solution-processed solar cell devices incorporating metal-halide perovskite semiconductors continue to be broken, with the need for scalable process technology and optimized ink formulations highlighted for large-area prototypes. The study demonstrates the importance of rational insights into ink composition and process control for reproducible manufacturing of MHP-based devices. The addition of a limited amount of DMSO prevents the formation of an intermediate crystalline phase and promotes the formation of the desired perovskite phase, while excess DMSO content negatively impacts thin-film morphology.