Fig. 5

Static and transient absorption measurements of FAPbI₃. a Static temperature dependent absorbance from 80 K to 290 K in increments of 10 K. b Differential absorption spectra of the N–H stretching modes in the range of 3200 cm⁻¹ to 3500 cm⁻¹. c Transient spectral map taken at 80 K using 500 nm pump excitation (329 µJ cm⁻² fluence). The color-coded quantity is ΔOD (×1000). d Spectra of the two principle components (PCs) of the transient response shown in red (bleaching) and blue (photo-induced absorption, or PIA). Circles correspond to the pixels of the array detector. Inset: kinetics of the bleach principle component