Síntese e caracterização de nanocristais coloidais de perovskita CsPbBr₃: efeitos da dopagem com Cu²⁺ nas propriedades ópticas

Abstract

In recent years, colloidal perovskite nanocrystals (NCs) have attracted considerable attention due to their tunable optical properties and their strong potential for optoelectronic applications. In this context, this work investigates the synthesis of CsPbBr₃ NCs and the modulation of their optical properties through control of the synthetic environment and doping with Cu²⁺ ions. Initially, CsPbBr₃ NCs were synthesized using the ligand-assisted reprecipitation (LARP) method, employing different antisolvents, such as ethyl acetate, chlorobenzene, toluene, and chloroform, to evaluate the influence of the colloidal environment on nucleation, growth, and surface passivation processes. The obtained samples were characterized by optical absorption spectroscopy, steady-state photoluminescence (PL), and time-resolved photoluminescence (TRPL). The results revealed significant differences in the optical properties of the NCs as a function of the antisolvent employed. Less polar antisolvents, particularly toluene, favored the formation of NCs with narrower emission bands and a higher contribution of radiative recombination, indicating improved optical quality and colloidal stability. Based on these results, toluene was selected for the subsequent stage of the study, in which Cu²⁺- doped CsPbBr₃ NCs were synthesized at different nominal concentrations. These samples were characterized by optical absorption spectroscopy, PL, TRPL, X-ray diffraction, and Raman spectroscopy. Copper doping induced changes in the charge carrier recombination dynamics, indicating the influence of the dopant on both radiative and nonradiative channels of the material. Overall, the results demonstrate that control of the antisolvent and metallic doping constitutes an efficient strategy for engineering the optical properties of CsPbBr₃ perovskite nanocrystals, contributing to the understanding of these systems and to their potential use in optoelectronic applications.