Fully Printed HTL-Free MAPbI₃ Perovskite Solar Cells with Carbon Electrodes

This study investigates fully printed methylamine vapour-treated methylammonium lead iodide (MAPbI₃) hole transport layer (HTL)-free perovskite solar cells (PSCs) with a carbon electrode. We describe a method that can be used to deposit MAPbI₃ films in an ambient environment with doctor blading that is entirely free of spin coating and has precise morphology control, in which the varying input N₂ pressure affects the film morphology. Consequently, a fully printed perovskite solar cell with an ITO/SnO₂/MAPbI₃/carbon structure was fabricated using a doctor-blading SnO₂ electron transport layer and a screen-printed carbon counter electrode. The low-temperature-derived PSCs exhibited a superior power conversion efficiency (PCE) of 14.17% with an open-circuit voltage (V_oc) of 1.02 V on a small-active-area device and the highest efficiency of >8% for an illumination exposure area of 1.0 cm², with high reproducibility. This work highlights the potential of doctor blading and methylamine vapour treatment as promising methods for fabricating high-performance perovskite solar cells. A doctor-blading approach offers a wide processing window for versatile high-performance perovskite optoelectronics in the context of large-scale production.