Extended Data Fig. 5: Analysis of carrier dynamics in perovskite films.
From: High-performance tandem perovskite LEDs through interlayer photon recycling

a, Schematic illustration of samples prepared for transient PL measurements. b, Excitation light spectra with centre wavelengths at 660 nm, 750 nm and 780 nm, alongside absorption spectra for single FA1−xCsxPbI3-bottom and single FAPbI3-top films.