(274f) Chiroptically Resolved Refractive Index Characterization of Quasi-2D Chiral Lead-Halide Perovskites

Hybrid metal-halide perovskites (MHPs) have recently emerged as promising materials due to their remarkable light-absorbing and luminescent properties. In quasi-two-dimensional (quasi-2D) hybrid MHPs, chiral organic ligands can endow structural and optical chirality to the metal-halide network, enabling chiral optoelectronic applications such as chiral photoluminescence, chiral photodetection, and spintronics. The degree of chirality in chiral MHPs is represented by their circular dichroism (CD), defined as difference in optical absorbance between left-handed and right-handed circularly polarized light. However, traditional CD spectroscopy is performed on thin film samples in transmission configuration, and the results are dependent on material thickness, film morphology, and substrates. Here, we propose a generalizable approach to characterize the circular polarization-dependent complex refractive index for quasi-2D chiral perovskites. The chiral complex refractive index serves as a more intrinsic parameter to evaluate the degree of chirality of 2DHPs. Our study provides fundamental insights regarding how chiral ligands impact the intrinsic material optical property and provide guiding principles for the design of chiral perovskites optoelectronic devices.