Hybrid perovskite films deposited by thermal evaporation from a single source

Hybrid perovskites, such as MAPbI_3, are very promising materials to fabricate highly efficient and low-cost solar cells and photodetectors. In this work, we propose a new method of deposition of hybrid perovskite thin films through thermal evaporation of MAPbI₃ powder from a single source for which was evaluated the effect of evaporation parameters (distance, time, substrate temperature, chamber pressure, and crucible heating rate) on the structural, optical, and morphological properties. It was found that it is necessary to control adequately the chamber partial pressure, substrate temperature, and the crucible heating rate in order to obtain single-phase MAPbI₃ perovskite films. Also, it was studied the solvent annealing treatment as a method to increase the grain size of evaporated films. Finally, a study of transient and steady-state photoconductivity allowed verifying that the evaporated MAPbI₃ films present fast band to band photogeneration and bimolecular recombination, and also that the grain size growth leads to an increase of the photoconductivity intensity due to the improvement of the diffusion length.