Cavity-Enhanced Raman Scattering from 2D Hybrid Perovskites

TL;DR

This paper demonstrates a novel cavity-enhanced method to significantly boost Raman signals from 2D hybrid perovskites, enabling better characterization of their phonon properties despite their fragile nature.

Contribution

The study introduces an open-cavity setup with a gold substrate to enhance Raman scattering in 2D HOIPs, achieving a 15x signal increase through the Purcell effect.

Findings

15x enhancement of Raman signals observed

Effective approach for studying phonons in fragile 2D materials

Method applicable to other layered van der Waals crystals

Abstract

Two-dimensional (2D) hybrid organic-inorganic perovskites (HOIPs) are promising candidates for optoelectronic applications due to their efficient light emission properties, and strong dielectric confinement effects. Raman spectroscopy is a versatile, non-contact and often non-destructive technique, widely used to characterize crystalline materials. However, the inherently weak phonon scattering, strong background, and complex nature of the Raman signals from HOIPs present challenges in obtaining reliable signals. Further, the fragile nature of the 2D HOIP crystals results in rapid degradation upon exposure to heat, light and moisture, which presents further difficulty in enhancing Raman scattered photon signals. Herein, we report a novel approach to enhance the weak Raman scattering signals in Ruddlesden-Popper (RP) phase HOIPs by introducing an open-cavity comprising HOIP crystals on a gold substrate. We observe 15x enhancement of the Raman signals due to the Purcell effect inside the high-index HOIP crystals. Our simple approach can be extended to enhance the study of phonon scattering in other HOIP and van der Waals layered crystals.