Optical Constants and Effective-Medium Origins of Large Optical Anisotropies in Layered Hybrid Organic/Inorganic Perovskites

TitleOptical Constants and Effective-Medium Origins of Large Optical Anisotropies in Layered Hybrid Organic/Inorganic Perovskites
Publication TypeJournal Article
Year of Publication2019
AuthorsDeCrescent, Ryan A., Naveen R. Venkatesan, Clayton J. Dahlman, Rhys M. Kennard, Michael L. Chabinyc, and Jon A. Schuller
JournalACS Nano
Abstract

Hybrid organic/inorganic perovskites (HOIPs) are of great interest for optoelectronic applications due to their quality electronic and optical properties and the exceptional ease of room-temperature synthesis. Layered HOIP structures, e.g., Ruddlesden–Popper phases, offer additional synthetic means to define self-assembling multiple quantum well structures. Measurements of Ruddlesden–Popper HOIP optical constants are currently lacking, but are critical for both a fundamental understanding as well as optoelectronic device design. Here, we use momentum-resolved optical techniques to measure error-constrained complex uniaxial optical constants of layered lead-iodide perovskites incorporating a variety of organic spacer molecules. We demonstrate how large optical anisotropies measured in these materials arise primarily from classical dielectric inhomogeneities rather than the two-dimensional nature of the electronic states. We subsequently show how variations among these materials can be understood within a classical effective-medium model that accounts for dielectric inhomogeneity. We find agreement between experimentally inferred dielectric properties and quantum-mechanical calculations only after accounting for these purely classical effects. This work provides a library of optical constants for this class of materials and clarifies the origins of large absorption and photoluminescence anisotropies witnessed in these and other layered nanomaterials.

URLhttps://doi.org/10.1021/acsnano.9b05504
DOI10.1021/acsnano.9b05504