Hybrid lead halide iodide and lead halide bromide in efficient hole conductor free perovskite solar cell

In this work we used CH₃NH₃PbI_nBr _3-n (where 0 ≤ n ≤ 3) as hole conductor and light harvester in the solar cell. Various concentrations of methylammonium iodide and methylammonium bromide were studied which reveal that any composition of the hybrid CH₃NH₃PbI_nBr_3-n can conduct holes. The hybrid perovskite was deposited in two steps, separating it to two precursors to allow better control of the perovskite composition and efficient tuning of its band gap. The X-ray diffraction reveals the change in the lattice parameter due to the introducing of the Br^- ions. The hybrid iodide/bromide perovskite hole conductor free solar cells show very good stability, their power conversion efficiency achieved 8.54% under 1 sun illumination with current density of 16.2 mA/cm². The results of this work open the possibility for graded structure of perovskite solar cells without the need for hole conductor.