Synthesis of Hybrid Lead Iodide Perovskite Thin Film by Two-Step Method Modified with a Double Dipping Circle to Control Its Crystallization and Morphology to Improve Solar Cells’ Performance

Abstract

Crystallization and morphology of perovskite film played an important role to obtain efficient performance of perovskite solar cells. This study is aimed at optimizing the fabrication of hybrid organic–inorganic lead iodide perovskite layer by a two-step method modified by a double dip coating process which enables to control the perovskite crystallization and morphology. The duration time of each circle for the step of dipping PbI2 film to methylammonium iodide solution was varied from 90 to 240 second. The obtained perovskite films were characterized by X-ray diffraction to evaluate the transformation of PbI2 reactant to the perovskite product and its crystallization, by scanning electron microscopy to observe its morphology. Then, the perovskite films were implemented in functional perovskite solar cell devices followed by current–voltage characterization. Results showed that the perovskite was formed via an equilibrium process which reached an optimum transformation of PbI2 to the product after $2\times 150$  second circle dip coating, and its morphology was smooth with the least voids. The solar cell devices fabricated at the optimum conditions achieved a comparable performance of about 14%.