Ionic Liquids-Enabled Efficient and Stable Perovskite Photovoltaics: Progress and Challenges

Perovskite solar cells (PSCs) have been recognized as the best candidates for next-generation photovoltaics. However, it is still challenging to fabricate PSCs that are both efficient and stable. Ionic liquids (ILs) are a kind of molten salt at room temperature, possessing unique advantages that enable their widespread application in many fields. Notably, ILs have been shown to play versatile functions in realizing efficient and stable PSCs. Herein, we summarize advanced progress in ILs-based perovskite photovoltaics, focusing on the crucial functions of ILs in the processing of PSCs. First, the characteristics of ILs are systematically introduced to address their merits for application in PSCs. Sequentially, the key roles ILs play in the modification of functional layers in PSCs are categorically discussed, including film-forming dynamics control, chemical passivation, stability improvement, and innovative alternatives to traditional materials. Finally, we give some enlightening viewpoints for the design of ILs toward high-performing PSCs.