Microstructural and optical properties of HC(NH_2)_2PbI_3 thin films prepared by single source thermal evaporation

摘要

AbstractThe HC(NH2)2PbI3thin films as the perovskite solar cells absorption layer were prepared by single-source thermal evaporation. The stoichiometric ratio effects of HC(NH2)2I/PbI2precursors on the properties of HC(NH2)2PbI3thin films were investigated. The microstructure, surface morphology and optical properties of HC(NH2)2PbI3thin films were characterized by X-ray diffraction (XRD), energy dispersive spectroscope, scanning electron microscopy and spectrophotometer respectively. The results show that, with stoichiometric ratio of FAI/PbI23:1, the XRD results of formamidine lead iodine thin films prepared by single source thermal evaporation indicated the typical peaks of HC(NH2)2PbI3thin films with few impurities. The dense and uniform films were formed with large crystal grains on the surface and high crystallization. The Pb/I element ratio was approximate to the ideal stoichiometric ratio of HC(NH2)2PbI3thin films. The band gap of the HC(NH2)2PbI3thin film calculated was 1.5 eV, which satisfied the optical properties requirement of absorbers for perovskite solar cell applications, making them potential applicable for large-area efficient perovskite solar cells.