Numerical analysis of flow parameters for perovskite layer printing with a slot-die head integrated 3D printer

The manufacturing of perovskite solar cells (PSCs) over large substrates with high efficiency remains a significant challenge. In this regard, integrating 3D printing technology with conventional PSC fabrication methods can be a viable option as it offers efficient material utilization and the potential for scalability. This research focuses on numerical optimization of flow parameters for the practical printing of perovskite solution through the integration of a slot-die head into an extrusion-based 3D printer. The numerical analysis was performed using computational fluid dynamics (CFD) in ANSYS Fluent, employing the finite volume method (FVM) to simulate the flow behavior of a perovskite (methylammonium lead triiodide – chloride (CH₃NH₃PbI₃₋ₓClₓ)) solution. CFD simulations were employed to evaluate velocity and pressure distributions at various inlet velocities, specifically 3 mm/s, 4 mm/s, and 5 mm/s. The analysis revealed that an inlet velocity of 3 mm/s maintained stable laminar flow, which is essential for achieving high coating uniformity. Conversely, higher velocities introduced turbulence, thereby compromising film uniformity. To validate the simulation results, an experimental test was conducted at the optimal inlet velocity of 3 mm/s using a 3D-printer-integrated slot-die head. Characterization via Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) demonstrated that the resulting thin films possessed surface morphologies and crystalline structures comparable to those produced by traditional spin-coating. These results provide a foundational framework for utilizing 3D printing technology in the scalable fabrication of PSCs.