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High Resolution Phonon-assisted Quasi-resonance Fluorescence Spectroscopy
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Spectroscopic signatures of biexcitons: A case study in Ruddlesden-Popper lead-halides
Katherine A Koch1, Esteban Rojas-Gatjens2, Martín Gómez-Dominguez3
1Department of Physics and Center for Functional Materials, Wake Forest University, 2090 Eure Drive, Winston-Salem, North Carolina 27109, USA.
The Journal of Chemical Physics
|July 18, 2025
Summary
This study reveals how exciton-exciton interactions in 2D perovskites create biexcitons. Advanced spectroscopy accurately characterizes these biexcitons, including mixed types, crucial for semiconductor light-emitting applications.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Quantum Optics
Background:
- Exciton-exciton interactions govern semiconductor light emission.
- Two-dimensional (2D) Ruddlesden-Popper perovskites exhibit distinct excitonic resonances (X1, X2).
- These resonances facilitate the formation of self- and cross-coupled biexcitons.
Purpose of the Study:
- Investigate biexciton binding energies and spectroscopic signatures in 2D Ruddlesden-Popper perovskites.
- Differentiate between self- and cross-coupled biexciton formation.
- Assess the efficacy of photoluminescence (PL) versus two-dimensional electronic spectroscopy (2DES) for biexciton characterization.
Main Methods:
- Employed photoluminescence (PL) spectroscopy.
- Utilized two variations of two-dimensional electronic spectroscopy (2DES).
- Mapped one-quantum and two-quantum correlations to analyze biexciton dynamics.
Main Results:
- Photoluminescence spectroscopy showed limitations due to spectral broadening and reabsorption.
- Two-dimensional electronic spectroscopy provided accurate characterization of multiple biexciton states.
- Identified mixed biexcitons resulting from exciton cross-coupling.
Conclusions:
- Advanced 2DES is superior to PL for characterizing biexcitons and their binding energies in these materials.
- Uncovered new insights into many-body interactions, specifically exciton-polarons.
- Findings advance understanding of light-matter interactions in layered perovskites for optoelectronic applications.
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