Fig. 1: Ultrafast dynamics study in quasi-2D Ruddlesden-Popper perovskites.

a The schematic depicts the 2DES (Two-Dimensional Electronic Spectroscopy) experiment aimed at studying ultrafast photoinduced dynamics in hot drop-cast quasi-2D Ruddlesden-Popper perovskite films, which exhibit a sandwich-like phase distribution. A microscopic representation of the 2D perovskite film on a quartz substrate is also shown. b The laser spectrum (shaded in green) utilized in the 2DES experiment is overlaid with the experimental linear absorption spectrum (depicted by the red line). The excitonic transitions within the 2D perovskites of varying layers are indicated by dashed lines, referencing values from previous literature reports36,42.