Visualizing the Redox Reaction Dynamics of Perovskite Nanocrystals in Real and Reciprocal Space.

Redox reaction, involving the gain and loss of electrons between reactants, is one type of common chemical reaction governing fundamental energy issues in nature. However, reports of vividly visualizing such key processes with simultaneous structural determination of new phases that are involved are rare. Here, by achieving simultaneous recording in both real and reciprocal space, we demonstrate in situ imaging of the redox reaction dynamics in perovskite nanocrystals. The thorough atomic-scale movies enable an in-depth understanding of the reaction-induced nucleation and growth mechanism of clusters with the aid of carbon, and a simple way of using SiN films at room temperature to fully prevent the irradiation-induced degradation in perovskites is proposed, in contrast to the costly low-temperature strategy. Real-time atomic-scale imaging in both real and reciprocal space paves the way for revealing various chemical and physical events at targeted nanoscale positions with complementary structural information.