Synthesis of Perovskite Thin Films (FAPbBr1.6I1.4) by Spin Coating Technique for Tandem Solar Cells

In this work, we have optimized the deposition parameters of the FAPbBr _1.6 I _1.4 perovskite thin films by the spin coating technique, namely the deposition speed and the centrifugation time. The thin layers of perovskite FAPbBr _1.6 I _1.4 were prepared by mixing the solution of PbBr ₂ : DMF: DMSO and FAI: IPA and deposited on glass substrates by the one-step spin coating technique. Morpho-structural and optical techniques were used for the characterization of fabricated thin films. The results show that the variation of the speed and the centrifugation time has a significant effect on the morphology and optical properties of the FAPbBr _1.6 I _1.4 perovskite thin films. The structural characterization of the FAPbBr _1.6 I _1.4 films revealed the presence of the perovskite structure in a single cubic α-FAPbBr1.6I1.4 phase independently of the deposition conditions. The optimized thin film was deposited by spin coating at 4000 rpm during 30s has a band gap energy of 1.83 eV. Such a gap suitable for a top cell as tandem configuration with silicon bottom cell.