Organic-Inorganic Perovskite Fluorides and Composites

Hybrid organic-inorganic perovskites incorporating fluoride ions are emerging as a promising next-generation material platform for optoelectronics, energy storage, and catalysis. Compared to their counterparts, fluoride perovskites offer superior thermal and chemical stability, lower defect densities, and greater resistance to moisture. These benefits stem from the strong ionic bonding conferred by highly electronegative fluoride ions, which enhance structural integrity and suppress defect formation. The chapter explores diverse fluoride perovskite chemistries, focusing on systems incorporating divalent transition metals (e.g., Mn, Co, Ni) and linear diamines (e.g., 1,3-diaminopropane, 1,4-diaminobutane), revealing how dimensionality, symmetry, and magnetic properties are tuned by these choices. Hydrothermal and solvothermal synthesis methods are discussed, emphasizing the role of carbon chain parity in directing 2D versus 3D structures. Case studies, such as (enH 2 )MnF 4 , (pnH 2 )CoF 4 , and (bnH 2 )BF 4 , illustrate structure-property relationships, including bandgap tunability and charge carrier mobility. Potential for multiferroicity, enabled by asymmetric organic cations, is highlighted as a frontier area. Finally, the chapter examines key application areas, from stable perovskite solar cells and LEDs to supercapacitors and spintronic platforms, while addressing scale-up challenges and future research directions. Collectively, this chapter positions hybrid fluoride perovskites as chemically robust, tunable, and multifunctional materials poised to impact a wide range of emerging technologies.