MAPbI3 Deposition by LV-PSE on TiO2 for Photovoltaic Application

Hybrid perovskite is one of the most popular materials nowadays due to its very exclusive properties. In this work we have compared MAPbI3 prepared by a “fully solvent-free” process namely two steps Low-Vacuum Proximity-Space-Effusion (LV-PSE) and a two steps physical-chemical technique. In the first one the substrate is located close to the melting pot and is self-heated by the reagents powder that are evaporated in a low vacuum chamber. In the second one PbI2 is evaporated as in the first one while the conversion into MAPbI3 is obtained by dipping the PbI2 film into a MAI solution. The layers deposited were characterized in terms of crystal structure by XRD analyses, that showed the presence only of the main peak related to the MAPbI3 structure, and in terms of morphology by SEM/TEM analyses that revealed a flat uniform coverage of the substrates on flat substrates while flake grain shape on rough FTO substrates. As proof of concept, solar cell architectures were prepared using Spiro-MEOTAD as Hole Transporting Layer and gold to exploit the new up-scalable and clean deposition method.