DMF-free co-solvent doctor-bladed FA0.6MA0.4PbI3 perovskite solar cells and modules under ambient conditions

Abstract

Perovskite solar cells (PSCs), recognized for their high efficiency and scalable manufacturing potential, face significant challenges in achieving uniform, high-quality large-area films via ambient doctor-blading techniques, particularly due to limitations in conventional solvent systems. This study addresses the critical need for solvent systems capable of serving as viable alternatives to conventional solvent, while simultaneously optimizing crystallization kinetics and film morphology under ambient conditions. We demonstrate a N, N-dimethylformamide (DMF)-free co-solvent strategy utilizing 2-methoxyethanol (2-ME) and N-methyl-2-pyrrolidone (NMP) to precisely modulate solvent evaporation dynamics and perovskite nucleation. The weak coordination of Pb2+ by 2-ME promotes rapid volatilization, while the strong coordination by NMP stabilizes the intermediates and delays surface nucleation, enabling uniform crystallization and dense films formation. The optimized NMP improved crystallinity, reduced non-radiative recombination, and boosted charge transport, enhancing power conversion efficiency (PCE) from 20.18% to 23.43%. Furthermore, a mini-module (10.3 cm2) fabricated under the same conditions achieved a PCE of 19.08%, underscoring the scalability and applicability of the proposed approach. These findings suggest that the DMF-free co-solvent strategy is highly effective for the scalable fabrication of large-area PSC modules and offers a promising pathway toward their commercialization.