Estudo da incorporação de pontos quânticos semicondutores em matrizes poliméricas

Abstract

Due to their nanometric size and crystalline nature, quantum dots (QDs) are materials with optical properties that are widely studied for various types of applications. Otherwise, Polyaniline (PANI) is a well-known semiconductor polymer, which has structural properties that can be attributed in different means. We also use poly (lactic acid) (PLA), which is biodegradable, obtained from renewable sources and has physical and mechanical properties that make it possible to be used in the extrusion of filament for 3D printing. The combination of these polymeric materials with semiconductor nanoparticles can lead to the formation of nanocomposites with different characteristics from the isolated materials. In the first stage of this work, we performed the chemical synthesis of CdSe semiconductor nanoparticles (QDs) with varying sizes. The optical characteristics of QDs were verified with absorption spectroscopy and photoluminescence techniques, which showed the wavelengths of absorption, emission and the size of the nanoparticles. The following nanocomposites in the form of films, PANI/CdSe and PLA/CdSe were synthesized. These films were characterized by microscopy and spectroscopy techniques to study the vibrations of the bonds, structural and fluorescence information. The characterizations revealed some information about the nanocomposites, it was possible to identify that, for certain amounts of PANI used in the formation of the film, it make the luminescence of the QD to be minimized. For the PLA/QD film, the insertion of the nanoparticles in the polymeric matrix does not cause major interference in the optical absorption spectrum. Finally, we consider that further characterizations are necessary to verify all the mechanisms of interaction between the QDs and the polymeric matrices.