Síntese e caracterização de derivado do dicetopirrolopirrol para a detecção de ozônio na atmosfera com possível aplicação em dispositivos optoeletrônicos

Abstract

Ozone is a highly reactive oxidant that is harmful to humans. Despite this, its applications have increased in recent years, such as in aesthetic and health treatments, which generates a demand for devices that can detect and quantify ozone in a simple and fast way. Conjugated molecules and polymers have been widely used in optoelectronic devices capable of detecting different analytes at very low concentrations (of the order of ppb). One of the simplest ways of detection is through colorimetric assays. For example, diketopyrrolopyrrole (DPP) derivatives show an intense fluorescence emission at 550 nm, which decreases in intensity in the presence of extinguishing agents (“quenchers”), such as ozone. In this work, an optoelectronic device capable of detecting ozone was developed using the DPP derivative. The DPP derivative, 3,6-dithiophene-2-yl-2,5-di(hexyl)-pyrrolo[3,4-c]pyrrole-1,4-dione, was synthesized from the reaction of DPP with n-bromohexyl. Initial tests were performed with known concentrations of ozone. For this, a commercial ozone generator was used and a gas dilution system was set up. The concentration was determined using the potassium iodide reference method (pH = 6.8 + 0.2), which consists of the oxidation of iodide to iodine and subsequent quantification using molecular absorption spectroscopy (350 nm). With the exposure of ozone gas on the DPP derivative, tests were carried out with different sampling times. The ozone concentration in the system is 68.39 ppb and was determined from the data obtained through the absorption spectroscopy technique in the UV-Vis region. DPPH fluorescence decreases by 59.64% with 10 minutes of exposure to O3. Results indicated that the use of the DPP derivative in a dual platform optical sensor for ozone detection is promising.