Vlad Michaelis

NMR Spectroscopy of Metal Halide Materials: Shining Opportunities
& Challenging Nuclei

Metal halide perovskites are a fascinating class of materials with far-reaching potential in various applications, including photovoltaics,
photodetectors, light-emitting diodes, quantum sensing, X-ray detectors, and lasers. While this broad class of compounds continues to evolve, their atomic-level structure and dynamics is immensely complex due to their high degree of chemical and synthetic variability that allows their physical, optical and chemical properties to be tuned. This flexibility accommodates organic and inorganic cations, changes in valency, and substitution abilities across Group 17. Further synthetic manipulation enhances our chemical design ambitions by enabling the exploration of new dimensionalities and stoichiometries (perovskite-inspired materials), as well as crystallite sizes (bulk to nano).

This presentation will discuss our efforts transitioning from Pb-based materials to Sn- or Ge-containing solids that were initially avoided due to their propensity to degrade rapidly but are now quickly gaining attention. We will discuss synthetic strategies, sample handling, and how we apply solid-state nuclear magnetic resonance (NMR) spectroscopy to understand degradation, phase stability, dynamics, cation/anion substitution, as well as heterovalent doping using both I=½ and quadrupolar (I>½) nuclei (207Pb,119Sn, 133Cs, 73Ge, 35Cl, 79Br). Our focus will be using NMR methods and considerations when accessing these nuclei, with some instances of the use of nuclear quadrupole resonance (NQR), dynamic nuclear polarization (DNP), or electron paramagnetic resonance (EPR).

8:00 AM California or 11:00 AM Boston or 5:00 PM Paris or 8:30 PM Delhi