Investigação das propriedades ópticas de nanocristais de Perovskita – CsPbI3 crescidos em matriz vítrea, dopados com íons de Neodímio - Nd3+

Abstract

The main objective of this work is to synthesize and characterize the optical, structural and electronic properties of Perovskite - CsPbI3 nanocrystals grown in a glass matrix, doped with Nd3+ ions. The synthesis process of the material was based on the melting of the reagents in an electric oven, followed by a sudden cooling, in order to control the rate of nucleation and growth of the nanocrystals, in addition to being the mechanism that formed the amorphous phase of the matrix, The glass. The material was thermally treated in an electric oven at different times, keeping the temperature constant, in order to verify the influence of the size of the nanocrystals in relation to the quantum confinement of the system. The analysis of the optical properties of the nanocrystals was performed by UV-Vis-NIR Optical Absorption Spectroscopy, Photoluminescence Spectroscopy and Fluorescence lifetime spectroscopy as a function of temperature. Structural characterizations were carried out by X-ray Diffraction, Transmission Electron Microscopy and Selected Area Electron Diffraction. As a result, experimental evidence showed the presence of energy transfer from CsPbI3 nanocrystals to Nd3+ ions embedded in glassy systems (SBNAPC: SiO2-B2O3–NaI–Al2O3–PbI2–Cs2CO3). The transfer of radiative and non-radiative energy between the Perovskite nanocrystals and the levels of Nd3+ ions could be observed in the photoluminescence spectra, and the main characteristic present was an absorption in the ultraviolet region and emission in the visible region. The results obtained demonstrate the presence of nanocrystals with a predominant structure of the orthorhombic type, and cubic structures can be found in some regions. Being these nanocrystals with an average size of 7 nm, which indicates the presence of a high quantum confinement of the system. It is believed that these results may inspire further investigation of similar systems in order to reach possible laser devices or applications. In addition, the glass matrix synthesis strategy proves to be effective in protecting nanocrystals from chemical attack in a hostile environment, ensuring long-term stability when compared to the colloidal system, since they are easily oxidized or inactivated in the presence of oxygen, moisture or light irradiation.