A study on lead halide perovskites: preparation and characterization

Abstract

This work deals with all-inorganic lead halide perovskite (LHP) nanocrystals and it mainly focuses on two different synthetic approaches. The first one is the conventional hot injection method where the reaction is conducted at high temperature and inert atmosphere. Instead, the second approach is a synthesis done at room temperature and developed to overcome some of the issues characterizing the hot injection method. In fact, the possibility to work at a lower temperature and atmospheric condition allows to utilize a greater amount of precursors, which could be useful for the possible scaling up of the whole process. Moreover, the approach developed into this thesis aims at improving some specific aspects among otherwise well-established room temperature procedures. To this purpose, the solvents generally used for synthesis at room temperature have been substituted with water and citric acid has been employed both as capping ligand and to control the pH of the solution to avoid the formation of lead hydroxide. The products obtained by both synthetic routes have been characterized by x-ray diffraction and electron microscopy. The characterization is mostly focused on the compounds obtained using the room temperature approach since this one is partly new and has not been previously inspected, so a wider comprehension of the obtained morphologies is required.