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Abstract Quasi‐2D metal halide perovskites (MHPs) are an emerging material platform for sustainable functional optoelectronics, but the uncontrollable, broad phase distribution remains a critical challenge for applications. Nevertheless, the basic principles for controlling phases in quasi‐2D MHPs remain poorly understood, due to the rapid crystallization kinetics during the conventional thin‐film fabrication process. Herein, a high‐throughput automated synthesis‐characterization‐analysis workflow is implemented to accelerate material exploration in formamidinium (FA)‐based quasi‐2D MHP compositional space, revealing the early‐stage phase growth behaviors fundamentally determining the phase distributions. Upon comprehensive exploration with varying synthesis conditions including 2D:3D composition ratios, antisolvent injection rates, and temperatures in an automated synthesis‐characterization platform, it is observed that the prominentn= 2 2D phase restricts the growth kinetics of 3D‐like phases—α‐FAPbI3MHPs with spacer‐coordinated surface—across the MHP compositions. Thermal annealing is a critical step for proper phase growth, although it can lead to the emergence of unwanted local PbI2crystallites. Additionally, fundamental insights into the precursor chemistry associated with spacer‐solvent interaction determining the quasi‐2D MHP morphologies and microstructures are demonstrated. The high‐throughput study provides comprehensive insights into the fundamental principles in quasi‐2D MHP phase control, enabling new control of the functionalities in complex materials systems for sustainable device applications.
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This content will become publicly available on December 1, 2025
Accelerating Materials Discovery by High‐Throughput GIWAXS Characterization of Quasi‐2D Formamidinium Metal Halide Perovskites
Abstract The intriguing functionalities of emerging quasi‐2D metal halide perovskites (MHPs) have led to further exploration of this material class for sustainable and scalable optoelectronic applications. However, the chemical complexities in precursors—primarily determined by the 2D:3D compositional ratio—result in uncontrolled phase heterogeneities in these materials, which compromises the optoelectronic performances. Yet, this phenomenon remains poorly understood due to the massive quasi‐2D compositional space. To systematically explore the fundamental principles, herein, a high‐throughput automated synthesis‐characterization workflow is designed and implemented to formamidinium (FA)‐based quasi‐2D MHP system. It is revealed that the stable 3D‐like phases, where the α‐FAPbI3surface is passivated by 2D spacers, exclusively emerge at the compositional range (35–55% of FAPbI3), deviating from the stoichiometric considerations. A quantitative crystallographic study via high‐throughput grazing‐incidence wide‐angle X‐ray scattering (GIWAXS) experiments integrated with automated peak analysis function quickly reveals that the 3D‐like phases are vertically aligned, facilitating vertical charge conduction that can be beneficial for optoelectronic applications. Together, this study uncovers the optimal 2D:3D compositional range for complex quasi‐2D MHP systems, realizing promising optoelectronic functionalities. The automated experimental workflow significantly accelerates materials discoveries and processing optimizations that are transferrable to other deposition methods, while providing fundamental insights into complex materials systems.
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- Award ID(s):
- 2043205
- PAR ID:
- 10575770
- Publisher / Repository:
- John Wiley & Sons, Inc
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 34
- Issue:
- 49
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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