Synthesis and characterization of perovskite FAPbBr3-x I x thin films for solar cells

FAPbI3, FAPbBr3, and FAPbBr3-xIx perovskite thin films were produced in a single step from a solution containing a mixture of FAI, PbI2, FABr, and PbBr2 (FA = formamidinium). FAPbBr3-xIx perovskite thin films were deposited onto ITO-coated glass substrates by spin coating. X-ray diffraction analyses confirmed that these thin-film perovskites crystallize in the cubic phase (Pm-3 m) for all composition range 0 B x B 3. Mixed lead perovskites showed a high absorbance in the UV-Vis range. The optical band gap was estimated from spectral absorbance measurements. It was found that the onset of the absorption edge for FAPbBr3-xIx thin films ranges between 1.47 and 2.20 eV for x = 0 and x = 3, respectively. Photoluminescence emission energies for mixed halide perovskites were also dependent on their composition and presented intermediate values from 810.4 nm for FAPbI3 to 547.3 nm for FAPbBr3. [GRAPHICS] .