Fig. 5: Schematic illustration of perovskite crystallization process with different lead-additive binding affinity.
From: Manipulating crystallization dynamics through chelating molecules for bright perovskite emitters
The additives with weak coordination affinities (e.g., MFAs) cause rapid perovskite nucleation at the initial stage of thermal annealing or even at room temperature. And those with strong affinity (e.g., CAs) bring about thermodynamically stable intermediates, resulting in highly emissive perovskites. The pink and yellow boxes illustrate the competitive ligand exchange between halides and additives with different binding affinity, as well as the respective evolution of thermal energy barrier (solid line) of perovskite crystallization compared to that without using additive (dash line). Here, Ea denotes the activation energy for crystallization, and ΔEa is the enhanced energy caused by additive coordination.
