Fig. 2
From: Cross-plane coherent acoustic phonons in two-dimensional organic-inorganic hybrid perovskites
Transient reflection measurements of the 2D RP single crystals. a–e ΔR/R spectral maps for N = 1–6, respectively, acquired with 400-nm pump excitation. The scalebar is in unit of ΔR/R (×1000). Fluences used were 0.18, 0.25, 0.25, 0.25, 0.18, and 0.21 mJ cm−2, respectively
