Design Rules for Two‐Dimensional Organic Semiconductor‐Incorporated Perovskites (OSiP) Gleaned from Thousands of Simulated Structures**

Abstract

Two‐dimensional (2D) halide perovskites are an attractive class of hybrid perovskites that have additional optoelectronic tunability due to their accommodation of relatively large organic ligands. Nevertheless, contemporary ligand design depends on either expensive trial‐and‐error testing of whether a ligand can be integrated within the lattice or conservative heuristics that unduly limit the scope of ligand chemistries. Here, the structural determinants of stable ligand incorporation within Ruddlesden‐Popper (RP) phase perovskites are established by molecular dynamics (MD) simulations of over ten‐thousand RP‐phase perovskites and training of machine learning classifiers capable of predicting structural stability based solely on generalizable ligand features. The simulation results show near‐perfect predictions of positive and negative literature examples, predict trade‐offs between several ligand features and stability, and ultimately predict an inexhaustibly large 2D‐compatible ligand design‐space.

Emerging Two-Dimensional Organic Semiconductor-Incorporated Perovskites─A Fascinating Family of Hybrid Electronic Materials

“…Synthesizing a conjugated ligand is a demanding process that usually requires several steps and isolation procedures to obtain products with high purity. Besides the work of predicting 2D perovskites using ML models reported by Lyu et al and Lin et al, , it is of interest to extend the current chemical scope with diverse structural combinations and scrutinize the structure–property relationships between ligands and the resulting 2D and quasi-2D perovskites.…”

“…In contrast, several ML models have been successfully trained to accelerate the finding of new 3D halide perovskites. Deep learning models, classical ML models, as well as a high-throughput screening frameworks have been developed to predict various electronic properties and aid ligand design with well-discovered features. − Lin et al recently published a molecular dynamics (MD) simulation study of over 10k prospective OSiPs to establish design rules for stable ligand incorporation (Figure d) . Due to the ability of the ligands to relax across unit cells, they found that ligands larger than the unit cell along one dimension can still be accommodated in many cases and that linker selection plays a critical role for several specific body chemistries.…”

“…(d) Molecular dynamics simulation approaches for ligand–perovskite stability prediction. Reprinted with permission under a Creative Commons CC-BY license from ref . Copyright 2023 The Authors, published by John Wiley and Sons.…”

“…6d). 116 Due to the ability of the ligands to relax across unit cells, they found that ligands larger than the unit cell along one dimension can still be accommodated in many cases and that linker selection plays a critical role for several specific body chemistries. These predictions were also experimentally validated by the synthesis of novel ligands and the formation of 2D perovskites.…”

2D and quasi-2D hybrid perovskites containing organic cations with an extended conjugated system: opportunities and challenges

“…Dou and co-workers recently performed a molecular dynamics (MD) study of over ten thousand simulated 2D HOIP structures, including an algorithmically generated set of prospective cation chemistries and all previously reported experimental primary ammonium cations based on C, H, O, S, and N, with the goal to obtain the structural determinants of organic cation incorporation and 2D HOIP stability. 76 In terms of molecular design, they found that the overall stability trend of a 2D HOIP for a given cation is more strongly constrained by the molecular structure of the organic core than by the side-chains substituted onto that core or by the structure of the spacer between the core and the ammonium group. Organic cores composed of combinations of larger repeating units result in 2D HOIP structures with a lower average structural stability.…”