Room Temperature Synthesis of Formamidinium Lead Iodide (FAPbI3) Perovskite for Low-Cost Absorber in Solar Cells
Abstract
We report room temperature synthesis technique for the formamidinium lead iodide (FAPbI3) perovskite. The low-cost sequential room temperature chemical synthesis technique resulted in formation of α-phase FAPbI3, suitable for solar cell absorber application. The chemical precursors formamidine acetate (CH4N2·xC2H4O2) and lead iodide (PbI2) were used in the process. The drop casted and spin coated films of FAPbI3 on soda-lime glass and were then annealed at temperature of 80 °C. The FAPbI3 materials films were characterized by X-ray diffraction, UV-Visible spectroscopy, photoluminescence (PL) measurements, and transmission electron microscopic (TEM) measurement. The X-ray diffraction pattern confirms α-phase of FAPbI3 perovskite. The crystallite size as calculated from x-ray diffraction was found to be 40 nm corresponding to (001) peak. UV-Visible analysis shown broad absorption with bandgap value of 1.55 eV. The PL analysis show emission peak at 727 nm with estimated bandgap to be a 1.57 eV, in agreement with the UV-Visible spectroscopy. TEM analysis confirms the crystalline phase of FAPbI3 material and the inter-planar spacing was deduced to be 0.62 nm. We conclude successful synthesis of FAPbI3 perovskite with desirable properties in α-phase composition of FAPbI3 that are suitable for solar cell application.