Enhancing Two-Dimensional Electronic Spectroscopy for Layered Halide Perovskites

The photophysics of layered halide perovskites reveals a rich disposition of exciton behavior. Two-dimensional electronic spectroscopy (2DES) is a powerful technique for investigating such excitonic interactions and dynamics. However, the wide spectral range of layered perovskites presents a challenge in studies utilizing conventional 2DES setups to simultaneously probe their interacting excitonic states. Herein, we put forward a versatile 2DES setup employing a hollow-core fiber compressor (HCFC) to generate stable and optimized broadband laser pulses (6 fs) covering a spectral range of 500-950 nm. 2D spectra with high temporal and spectral resolution are possible even with a pulse-shaper-based commercial 2DES setup. Application to a representative two-phase Ruddlesden-Popper perovskite thin film reveals well-defined signals at the diagonal and off-diagonal positions, indicative of exciton delocalization between the two transitions. Our straightforward modification of a commercial 2DES setup extends its capabilities to investigate the large family of layered perovskites currently under intense scrutiny in the development of perovskite optoelectronics.