Crystallization control of antisolvent-free perovskite films using alkali metal additives for improving efficiency and extending applicability of perovskite solar cells†

The antisolvent-free fabrication of perovskite solar cells (PSCs) is a promising approach to secure their reproducibility and scalability. However, achieving high efficiency and uniform crystallization without antisolvent remains a critical challenge. In this study, we introduce alkali metal salts as additives to control the crystallization process and enhance the photovoltaic (PV) properties of antisolvent-free PSCs. The incorporation of KPF₆ effectively modulates the perovskite growth kinetics, resulting in improved grain size, reduced defect density, and enhanced charge transport properties. As a result, the optimized PSCs exhibit a significant improvement in power conversion efficiency (PCE) compared to the reference devices without KPF₆. Moreover, the addition of KPF₆ enabled large-area and semi-transparent antisolvent-free perovskite layers with great uniformity. This work provides valuable insights into rational additive engineering for crystallization control to achieve high efficiency antisolvent-free PSCs, paving the way for the development of scalable PSCs and their broad applications.