Characterization of ion-assisted, coevaporated CH3NH3PbI3 thin films

Methylammonium Lead Iodide CH₃NH₃PbI₃ is an organometal halide perovskite system that is used as an absorber in solar cells. Coevaporation of Methylammonium Iodide (CH₃NH₃I) and Lead Iodide (PbI₂) requires treatment of the resulting CH₃NH₃PbI₃ thin film to catalyze the reaction between CH₃NH₃I and PbI₂ and create a pure perovskite phase. Two methods are studied: post-deposition annealing and ion-assisted deposition. Both routes aid in forming a pure perovskite phase. Annealing leads to highly crystalline thin films, and ion beam irradiation leads to more amorphous films. The effects that such crystal structure has on the material´s optical properties and morphology is explored.