Supporting Information

Supporting Information

Photoexcitation dynamics in solution-processed formamidinium lead iodide perovskite thin films for solar cell applications

Running Title: Optical properties of a hybrid perovskite

Hong-Hua Fang,¹ Feng Wang,² Sampson Adjokatse,¹ Ni Zhao,² Jacky Even,³ Maria Antonietta Loi¹

¹Photophysics & OptoElectronics, Zernike Institute for Advanced Materials, Nijenborgh 4, Groningen, 9747 AG, The Netherlands

²Department of Electronic Engineering, The Chinese University of Hong Kong, New Territories, Hong Kong

³Université Européenne de Bretagne, INSA, FOTON, UMR 6082, 35708 Rennes, France

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Figure S1. 2D pseudo-color plot of normalized emission spectra under pump fluence of 1.4 J/cm² at different temperature for FAPbI₃ starting from FAI/PbI₂ (a) and FAI/PbI₂+HI (b); the PL spectra are normalized at maximum intensity.

Figure S2. Photoluminescence spectra of FAPbI₃ at 5 K. The spectrum is fitted with two Gaussian peaks, and the energy gap between the two peaks is 15 meV.

Figure S3. Streak camera data showing the time-resolved PL emission at 5 K for FaPbI₃ thin films starting from (a) FAI/PbI₂ and (b) FAI/PbI₂+HI. PL spectra extracted after photoexcitation, showing the energy difference between two emissions. The energy difference is 18 meV for FaPbI₃ thin films starting from (c) FAI/PbI₂, and it is 15 meV for (d) FAI/PbI₂+HI.

Figure S4. Normalized photoluminescence spectra at varied excitation power. A blue-shift in ASE has been observed when the pump power was increased from 28 nJ/cm² to 6.7 J/cm².