Agradecimentos: Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515. The authors thank the Laboratorio Nacional de Luz Sincrotron (LNLS) for providing beamtime at XRD2. R.F.M. thanks the support from FAPESP - process numbers: 2016/02268-9 and 2017/11019-5. A.F.N., J.C.G. and R.F.M. gratefully acknowledge the support from FAPESP (the Sao Paulo Research Foundation, Process 2017/11986-5) and Shell and the strategic importance of the support given by ANP (Brazil’s National Oil, Natural Gas and Biofuels Agency) through the R&D levy regulation. The powder X-ray diffraction, structure refinement, and SAXS interpretation were supported as a part of the Center for Hybrid Organic Inorganic Semiconductors for Energy (CHOISE), an Energy Frontier Research Center Funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under award number DE-AC36-08G028308. R.K. acknowledges the NSF fellowship Ver menos

Abstract: 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 L2[FAPbI3]n-1PbI4 [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 BA2[FAPbI3]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 Ver menos