Proceedings of nanoGe International Conference on Perovskite Solar Cells, Photonics and Optoelectronics (NIPHO19)
DOI: https://doi.org/10.29363/nanoge.nipho.2019.054
Publication date: 21st November 2018
Formamidinium lead iodide (FAPbI3) is one of the most extensively studied perovskite materials due to its narrow band gap and high absorption coefficient, which makes it highly suitable for optoelectronic applications. Deposition from a solution containing lead iodide (PbI2) and formamidinium iodide (FAI) or by sequential deposition of PbI2 and FAI usually leads to the formation of films with poor morphology and unstable crystal structure that readily crystallizes into two different polymorphs: the photoinactive yellow phase and the photoactive black phase. In this work, 2D 2-phenylethylammonium lead iodide (PEA2PbI4) thin films are deposited by a scalable doctor-blade coating technique and used as a growth template for the high-quality 3D FAPbI3 perovskite thin films, which is obtained by organic cation exchange. We report the structural, morphological and optical properties of these converted 3D FAPbI3 perovskite films, which we compare to the directly deposited 3D FAPbI3 films. The converted FAPbI3 thin films are compact, smooth, highly oriented and exhibit better structural stability in comparison to the directly deposited 3D films. These results not only underscore the importance of the employed deposition techniques in the formation of highly crystalline and stable perovskite thin films but also reveal a strategy to easily obtain very compact perovskite layers using doctor-blade coating.