Absorption Dissymmetry Factor Enhancement: A Data-Driven Approach to Unravel the Synthesis Knobs of Chiral 2D Perovskites

Chiral 2D metal halide perovskites (MHPs) hold promise for next-generation spin-optoelectronic applications. While still in early-stage development, significant efforts have focused on optimizing the dissymmetry factor (g), particularly in terms of their circular dichroism (gabs), which quantifies the chiroptical response related to the differential absorption of left and right circularly-polarized light. These materials typically exhibit intrinsically low gabs values (10-3), with variations spanning two orders of magnitude due to co-dependent structural, morphological, and experimental factors. Here, Pearson correlation analysis identified solvent choice as the primary factor governing gabs variability in chiral 2D MHP thin films based on R-/S-𝛼-methylbenzylammonium. Subsequently, a combination of Pearson correlation, ANOVA, and Gaussian process regression revealed that, for acetonitrile-based samples, film thickness and annealing temperature are the key parameters for optimizing gabs. In contrast, films prepared with higher boiling point solvents exhibit a more complex interdependence of gabs with annealing temperature, excitonic integral intensity, and film texture. The statistical analysis of the synthesis-chiroptical property relationship provides a foundation for the rational design of chiral 2D MHPs, while also guiding the exploration of alternative chiral cations, compositions, and deposition strategies.