A two-step spin-spray deposition processing route for production of halide perovskite solar cell

We report on fabrication of halide perovskite solar cells using a two-step spin-spray coating rout. The applied method is one of the most straight forward procedures for fabricating uniform stoichiometry and crystalline perovskite cells. To fabricate a high quality perovskite layer, various concentrations of methyl-ammonium iodide (CH3NH3I) were sprayed on a spin coated PbI2 layer using a simple airbrush gun. The characterization results indicate that the size of cuboid perovskite morphology depends on the concentration of methylammonium iodide in the spray procedure. The photovoltaic performance of the fabricated solar cells has been measured and a high dependency on the cuboid sizes was obtained. An average efficiency of 9.2% is obtained from the best solution of methylammonium iodide with the concentration of 7 mg/ml. The electron microscopy images of the perovskite cuboids in this concentration show that the cuboids' sizes are in the range of exciton diffusion length of the charge carriers. In addition, investigating the effect of presence of moderate moisture in the fabrication process shows no remarkable dependency of the photovoltaic parameters on the moisture percentage.