Synthesis and optoelectronic characterization of 2D/3D MAPbBr3

Excellent optoelectronic properties make perovskites the most promising materials for producing high efficiency optoelectronic devices.3D perovskites, present a strong ions migrations and an easy moisture degradation that make them no ready for industrial use.2D perovskites show a better resistance to moisture, but they are less efficient materials compared to 3D.2D/3D perovskites could be the best compromise between 3D and 2D perovskite in order to achieve high optoelectronic performance. 2D/3D perovskite structure combines the stability and high resistance to moisture of 2D perovskites with good optical and charge carrier transport properties of 3D perovskites. The aim of this work is to find the best process to fabricate 2D/3D MAPbBr3 perovskites structure and to verify if the construction of a thin 2D perovskite layer on the 3D surface has passivated the surface defects and has improved the charge transport in 3D perovskite. The study on fabrication process of 2D/3D perovskites was performed at Neèl Institute (CNRS),Grenoble(Fr). It consisted on verifying through optical and SEM microscope image, absorbance, PL and XRD measurements the formation of 2D perovskite layer on surface MAPbBr3 thin films after being treated with three different 2D perovskite solutions(PEA+Toluene,PEA+IPA,PEABr+IPA) for three diverse reaction time(30'',3',10').The study on the charge transport and defect states was carried out at the Department of Physics and Astronomy of University of Bologna. It consisted on performing I-V and PICTS measurements on pristine and treated with PEA+Toluene thin films for 15'', 1',10' and single crystals for 15'' and 1'.The times of treatment were chosen for such samples in order to study a case in which the treatment does not form a 2Dperovskite and a case in which it forms with one or two layers of 2Dperovskite.Current voltage characteristics and photocurrent analyses allowed for a detailed investigation of charge transport phenomena in 2D/3Dperovskites.