Progress in Multifunctional Molecules for Perovskite Solar Cells

Organic-inorganic halide perovskite solar cells (PSCs) have recently attracted much attention with the recent certified power conversion efficiency (PCE) record exceeding 24%. To date, many approaches have been developed for producing high-performance PSCs, in which the application of multifunctional molecules plays an important role. The multifunctional molecules can modify the morphology of perovskite films and/or passivate the surface defects through interactions with the perovskites' boundaries and/or the charge carrier extraction interfaces. As a result, both the PCEs and the stability of PSCs are improved. The recent progress in the development of multifunctional molecules-incorporated PSCs is reviewed. The importance of further understanding of the role of the multifunctional molecules in the perovskite film formation process and defect passivation mechanism is discussed. Further research in terms of multifunctional molecules can help to develop high-performance devices with long-term stability for future practical applications of PSCs.