[(CH₃)₃NCH₂CH₂NH₃] SNl₄: A layered perovskite with quaternary/primary ammonium dications and short interlayer iodine-iodine contacts

The organic-inorganic hybrid [(CH3)3NCH2CH2NH3] Snl4 presents a layered perovskite structure, templated by an organic dication containing both a primary and a quaternary ammonium group. Due to the high charge density and small size of the organic cation, the separation of the perovskite layers is small and short iodine-iodine contacts of 4.19 Å are formed between the layers. Optical thin-film measurements on this compound indicate a significant red shift of the exciton peak (630 nm) associated with the band gap, as compared with other Snl42--based layered perovskite structures.