Advanced X-ray Characterization of Pb-free perovskite nanomaterials

The project is the joint effort of an Italian team of researchers belonging to CNR-IC in close collaboration with the IIT, and a Brazilian team working at the novel LNLS synchrotron radiation source (SIRIUS). It aims to study chemical and structural transformations of novel Pb-free perovskites nanomaterials. Lead-based perovskites are currently the gold standard of perovskites for photovoltaics and light emission. However, the intrinsic toxicity of Pb2+ ions is a limit for the widespread application of these materials and has stimulated the search for less toxic alternatives, whose synthesis and characterization are the main target of this proposal.

The structure of halide perovskites (ABX3) is formed by a three-dimensional network of corner-sharing [BX6]4- octahedra (where B stands for a divalent metal cation and X stands for Cl, Br, or I), stabilized by large A cations in between the octahedra. In few years, halide perovskites and perovskite-related structures have been studied in a variety of compositions, and their applications in light emitting and photovoltaic devices have been heavily pursued. Following a surge of interest in these materials, lead (Pb)-based halide perovskites nanocrystals (APbX3 formula.) are synthesized with high photoluminescence quantum yields, as valid candidates in light emitting diodes, lasers, solar cells and scintillators. The team of the IIT has been one of the initiators of the field of lead halide perovskite nanocrystals, with key contributions to the synthesis and their applications in devices. A long-lasting collaboration exists with the group of the CNR-IC. Moreover, the Italian group has a consolidated collaborative work with the Brazilian team at the LNLS, for the characterization of this kind of materials, either in the form of thin films or colloidal nanocrystals, using synchrotron techniques. With the SIRIUS source entering in operation, unique opportunities to unravel chemical and physical properties of these halide perovskites are becoming available.