Spatiotemporal Route to Understanding Metal Halide Perovskitoid Crystallization

Abstract

A spatiotemporal experimental route is reported for the antisolvent vapor diffusion crystal growth of metal halide perovskitoids. A computational analysis combining automated image capture and diffusion modeling enables the determination of the critical concentrations required for nucleation and crystal growth from a single experiment. Five different solvent systems and ten distinct organic ammonium iodide salts were investigated with lead iodide, from which nine previously unreported compounds were discovered. Automated image capture of the mother liquor and antisolvent vials was used to determine changes in solution meniscus positions and detect the nucleation event location. Matching the observations to a numerical solution of Fick’s second law diffusion model enables the calculation of reactant, solvent, and antisolvent concentrations at both the time and position of the first stable nucleation and crystal growth. A machine learning model was trained on the resulting data, and it reveals solvent- and amine-specific crystallization tendencies. Solvent systems that interact more weakly with dissolved lead species promote crystallization, while those with stronger interactions can prevent crystallization through increased solubilities. Organic amines that interact more strongly with inorganic components and exhibit greater rigidity are more likely to be incorporated into crystalline products.

Additive Molecules Adsorbed on Monolayer PbI2: Atomic Mechanism of Solvent Engineering for Perovskite Solar Cells

“…Different from the common notion of forming intimate solvent–Pb bonds, ,− our calculations reveal that for perfect PbI 2 , DMF and GBL molecules cannot form direct solvent–Pb 2+ bonding and their interactions are mediated by the vdW force with weak adsorption energy and charge transfer to PbI 2 . Other solvent bases, such as DMSO, THTO, NMP, and DPSO, have barely formed solvent–Pb bonds, which are separated by the top iodine plane, making the bonding partially screened and subject to repelling and steric restriction though they are still much stronger than the vdW-dominated DMF and GBL.…”

Collaborative methods to enhance reproducibility and accelerate discovery

“…56 The SD2 community applied collaboratively developed tools and methods-for example, automated data generation, preprocessing, normalization, and analysis-to several scientic questions. Among other advances, these efforts led to faster and more accurate predictions of protein stability, [58][59][60] faster discovery of perovskite crystals, 54,55,61 and more accurate predictions of the impact of synthetic biological circuits on host organisms. 62…”