Investigation of structural and optical properties of CH3NH3SnI3 Perovskite layers synthesized by one-step thermal evaporation technique

In this study, CH3NH3SnI3 Perovskite thin films were prepared on different substrates, Glass, FTO, and mesoporous TiO2 by easy and cheap thermal evaporation method in one step. Then, structural, morphology and optical properties of the layers were investigated. The XRD patterns and Raman spectra showed that all samples have α-phase tetragonal Perovskite structures and crystallinity, as well as the morphology of the samples significantly changes as the substrates changes. Investigation of the optical properties of the samples showed that despite small thickness of the layers (about 200 nm), the absorption coefficient of the layers (specially the layer grown on FTO substrate) is significantly large (in order of 105 cm-1). This result with the values of the bandgap of the layers (1.28-1.53 eV) show that the synthesized CH3NH3SnI3 Perovskite thin films are a very good candidate for using in solar cells as absorber layers.