Nanostructured Mechanochemically Prepared Hybrid Perovskites Based on PbI₂and Alkylammonium Halides for Optoelectronic Applications

The preparation of hybrid perovskites (HPs) with small and large organic cations with a solventless mechanochemical treatment of the mixture of lead iodide and alkylammonium halides is presented. X-ray diffraction and electron microscopy show that the use of the mechanochemical approach for synthesis of HPs with small cations (CH3NH3PbI2X, X = I, Br, Cl) leads to the formation of crystalline nanoparticles with uniform shapes and sizes that do not exceed 70 nm. At the same time, the mechanochemical synthesis of HPs with large organic cations, (C6H13NH3)2PbI2X2, induces the nanostructuration with the formation of 2D structures regardless of the stoichiometry of the initial reaction mixture. We show that our mechanochemically prepared HPs exhibit a photoluminescence whose colors depend on the size of the organic cations and the type of halide ions that could be used for different optoelectronic applications, for improving color rendering index of garnet-based white-light-emitting diodes in particular.