Hybrid Organic-Inorganic Perovskites
Abstract: Hybrid organic-inorganic perovskites are found in a number of families, particularly the halides (e.g., CH3NH3PbI3) and formates (e.g., [(CH3)2NH2]Zn(HCOO)3). The halides are attracting a great deal of current attention on account of their excellent performance as active layers in solar cells, where conversion efficiencies have increased from 3.8% in 2009 to more than 22% in 2017.
Our own work in this area has explored the use of tolerance factors to rationalize known structures and predict new ones. We have also examined the role of hydrogen bonding in hybrid perovskite halides, as well as their mechanical properties. Our current work focuses on the search for lead-free hybrid double perovskites, such as (CH3NH3)2KBiCl6, (CH3NH3)2TlBiBr6, (CH3NH3)2AgBiBr6, and (CH3NH3)2KLnCl6. The formates comprise an equally interesting group, exhibiting ferroelectricity, glassy and multiferroic behavior.
Some recent developments in this important area will be discussed, including the discovery of a new family of hybrid perovskites based on hypophosphite rather than formate linkers.