Synthesis of Polycrystalline Ruddlesden-Popper Organic Lead Halides and Their Growth Dynamics

Ruddlesden-Popper organic lead halides (RPOLHs) are in the material science spotlight because of their remarkable optoelectronic properties, tailorable compositions, and improved ambient stability over their three-dimensional perovskite analogues. In this report, we introduce a new synthesis method for RPOLHs with general composition L-2[FAPbI(3)](n-1)PbI4 [L = butylammonium (BA) or benzylammonium (BZA), FA = formamidinium, and n = 1 and 2]. Our method yields polycrystalline materials useful for thin-film fabrication for optoelectronic applications. Furthermore, we report the growth dynamics of BA(2)[FAPbI(3)]PbI4 using in situ small-angle X-ray scattering, revealing that the slabs grow within the first seconds of the reaction and then self-assemble into bulk crystallites.