Reaching Highly Uniform Perovskite Ink Flow from a Slot-Die Head Toward Printed Solar Cells

Large-scale manufacturing of perovskite solar cells (PSCs) requires the deposition of homogeneous and defect-free perovskite films on large-area substrates. Up to now, the knowledge developed for industrial slot-die processing has not been fully transferred to the perovskite photovoltaic community. Here, the deposition of uniform perovskite layers by slot-die coating (SDC). Computer fluid dynamics (CFD) simulations, experimental validation, and calculation of industrial uniformity parameters are demonstrated, which enabled to establish processing conditions for SDC of perovskite ink. This approach allowed for obtaining stable cross-web flow in the slot-die head resulting in the formation of a stable coating bead yielding uniform perovskite films. The best processing parameters are used for the fabrication of slot-die-coated PSCs, which showed a more homogeneous spatial distribution of photovoltaic parameters compared to their spin-coated counterparts. Better reproducibility observed in device performance is a step forward toward the commercialization of perovskite photovoltaic technology. For the first time, the industrial approach used for the optimization of slot-die coating is applied for the processing of perovskite inks that have special conditions such as low viscosity and in situ crystallization on the substrate.