Fig. 4: Transient absorption (TA) characteristics for 2D perovskite heterostructures and PEA2PbI4.
From: Establishing charge-transfer excitons in 2D perovskite heterostructures

a TA spectra for 2D perovskite heterostructured [(PEA2PbI4)0.95:(PEA2SnI4)0.05] film. b TA spectra for pristine PEA2PbI4 film. c TA dynamics plotted for band-to-band transition (513.8 nm), surface excitons (537.5 nm), and broad emission (657.3 nm) in 2D perovskite heterostructures.