Pseudohalide-Based Ionic Liquids: Advancing Crystallization Kinetics and Optoelectronic Properties in All-Inorganic Perovskite Solar Cells

This study delves into the innovative approach of enhancing the efficiency and stability of all-inorganic perovskite solar cells (I-PSCs) through the strategic incorporation of thiocyanate (SCN-) ions via pseudohalide-based ionic liquid (IL) configurations. This straightforward methodology has exhibited captivating advancements in the kinetics of crystallization as well as the optoelectronic characteristics of the resulting perovskite films. These developments hold the promise of enhancing not only the quality and uniformity of the films but also aspects such as band alignment and the efficacy of charge transfer mechanisms. Calculation results corroborate that the incorporation of 1-butyl-3-methylimidazolium thiocyanate (BmimSCN) led to a significant redistribution of electron state density and enhanced electron-donating properties, indicating a substantial electron transfer between the perovskite material and the IL. Notably, the engineered devices demonstrate a remarkable efficiency surpassing 15%, a substantial enhancement attributed to the synergistic effects of the SCN- ion. Additionally, this approach offers inherent stability benefits, thereby addressing a significant challenge in I-PSC technology. This IL maintains >90% of the initial efficiency after 600 h, while the control device decreased to <20% of its initial value after only 100 h. 1-butyl-3-methylimidazolium iodide (BmimI) is also employed to further investigate the effects of SCN- ions on device performance.