Crystallization Kinetics in a Glass-Forming Hybrid Metal Halide Perovskite

The recent discovery of glass-forming hybrid metal halide perovskite (MHP) semiconductors has opened the opportunity to explore their utility beyond the already celebrated fields of photovoltaics and light emitters, as enabled by their crystalline counterparts. Reversible switching phenomena between glassy and crystalline states further extends the potential application space, prospectively, to memory, computing, photonics, metamaterials, and phase change energy storage. To better identify the characteristic switching properties, the underlying kinetics of glass crystallization is studied for an exemplary glass-forming (S)-(−)-1-(1-naphthyl)ethylammonium lead bromide (SNPB) perovskite, using a combination of calorimetry, microscopy, and kinetic modeling techniques. The study shows an activation energy of ∼350 kJ/mol for the glass-crystalline transition and an Avrami parameter of n = 2.02 ± 0.11, and points to heterogeneous surface-mediated nucleation of crystallites with two-dimensional laminar growth in space. These results serve as an initial guide toward modeling the glass-crystallization kinetic effects in MHPs and to facilitate assessment of the suitability of the glass-forming MHPs for a broad range of prospective applications.