Molecular design and photovoltaic performance of a novel thiocyanate-based layered organometal perovskite material

• A layered thiocyanate-modified organometal perovskite material was prepared.
• Single crystal was acquired firstly in emerging SCN−-substituted perovskite.
• The material shows great solubility and crystallinity in low boiling-point solvent.
• 3.32% PCE and as much as 0.725 FF of the solar cell device was achieved.
• Excellent film morphology can be achieved without thermal annealing.

A novel layered organometal halide perovskite material (CH3NH3)2Pb(SCN)2I2 was acquired by replacing the iodide ions locating on the axial positions of CH3NH3PbI3 octahedron with thiocyanide anions. The molecular structure of this material was characterized by X-ray single crystal diffraction, through which the thiocyanides were proved to be coordinated as terminal ligands on the lead center. A variety of spectral tests reveal material’s energy gap (Eg) and valence band (VB) as 1.65 eV and −5.76 eV, respectively. The concentration of holes has also been located as up to 1.07 × 1014 cm−3 via Hall effect measurement. What is important, for the material shows great solubility and crystallinity in low boiling-point solvent tetrahydrofuran, excellent film morphology can be achieved via a convenient and practical one-step precursor solution-deposition method without thermal annealing. The fill factor (FF) of solar cell devices based on this material can be promoted as much as 0.725.