Solid state NMR and NQR spectroscopy for 'in situ' studies of metal halide perovskites

Over the past 15 years, metal halide perovskites (MHPs) have emerged as one of the most promising materials for next-generation solar cells, thanks to their remarkable optoelectronic properties. Despite this potential, their large-scale deployment is still hindered by the presence of lead in the most efficient perovskite compositions for photovoltaics, as well as by their instability under environmental factors, including light exposure. In this context, the first part of this PhD work focuses on SSNMR experiments conducted on MHP systems with enhanced stability and/or lead-free compositions. The second part, which represents the core of this thesis, is dedicated to the development of SSNMR and NQR instrumentation and experimental setups for in situ illumination studies, aimed at investigating the phenomenon of photoinduced halide segregation in MAPb(BrxI1-x)3 perovskites.